Human bite losses of the lower lip

In two years, in our hospital in Nigeria, we saw 16 patients with lower lip losses caused by human bites. These are presented, together with the methods used for early management and subsequent repair.     

Primary reconstruction of major human bite wounds of the face.

Primary reconstruction of 36 major human bite wounds of the face without clinical infection has been carried out successfully as late as the fourth day after the initial injury. Primary healing was achieved in all patients. The postoperative period was free from major infection in all patients except one, including the latecomers. Extensive bacteriologic studies reveal that the infection in human bite wounds occurs secondarily as invasion to devitalized tissue. We therefore consider that debridement of wound edges to eliminate the crushed devitalized tissue is the key to success.     

Management of human bite injuries of the hand.

On the basis of experience at the Ottawa Civic Hospital over the past 10 years, a classification of and protocol for the management of human bite injuries of the hand are presented. Early exploration of such wounds under local anesthesia improves the outcome by facilitating adequate cleansing of the wound and enabling deep structures to be visualized. In this way the risk of major sepsis and of the disability so frequently associated with these innocent-looking injuries can be reduced.     

Further refinements on the triangular flap closure of the cleft lip

Refinements in the triangular flap closure of the unilateral cleft lip are presented. Randall's mathematical interpretation of the Tennison repair has been extended by using a series of arcs to determine the crucial points which form the triangular flap. Using this easily taught method, an isosceles triangular flap can be plotted which will interdigitate into the noncleft side of the lip. Two symmetrical vertical distances on either side of the cleft are thus formed. This allows for a standardized repair which may be more readily taught than the rotation-advancement technique. In addition, flaps are created which are turned medically toward the cleft and are used to accentuate the philtral pout, close the nostril floor, and reinforce the lip repair, allowing closure of even extremely wide clefts in one stage. These refinements in using the triangular flap closure for the repair of the unilateral cleft lip are diagrammatically presented. We believe that these refinements enhance the results of this closure.     

Primary repair of bilateral cleft lip and nasal deformity.

LEARNING OBJECTIVES: After studying this article, the participant should be able to: 1. List five principles that guide synchronous repair of bilateral complete cleft lip and nasal deformity. 2. Explain how different growth rates for the principal nasolabial features are applied during primary repair. 3. Describe two approaches for positioning the alar cartilages to form the columella. 4. Discuss the influences on referral patterns for a newborn with bilateral cleft lip. --Traditional repair of bilateral cleft lip focused on labial closure but accentuated the nasal deformities, which were addressed later. By the end of the past century, single-staged labial closure had replaced the old multistaged procedures and the technical emphasis had begun to shift from secondary to primary nasal correction. Now, presurgical maxillary orthopedics sets the bony foundation for synchronous nasolabial repair and for closure of the alveolar clefts. The study of normal nasolabial growth and the typical stigmata of the conventional methods provides the necessary foreknowledge to guide surgical sculpture in three dimensions and to anticipate the fourth dimension. The convergence of several forces are changing referral lines for children born with bilateral cleft lip. These include affirmation of centers of excellence, surgeons' self-regulation, prenatal diagnosis, economics of health-care delivery, and increasing parental sophistication. These pressures are not necessarily in conflict. Care by a subspecialized plastic surgeon and experienced team is in the best interests of the child and the third-party payer.     

Primary closure of the split-thickness donor site

A simple method of improving the donor site of split-thickness skin grafting is presented. Advantages include fewer wound-care problems, decreased pain, and a more aesthetic donor site. The disadvantage of increased operating time and expense are well compensated for by this method.     

Bacteriology of human bite wound infections

This study was designed to define the bacteriology of infected soft-tissue wounds from human bites, and to compare this with the bacteriology of infected animal bites in humans as determined in previous studies. The specimens were collected from 57 patients presenting to emergency rooms at 12 locations around the country. Three hundred and eighty organisms were isolated (224 aerobes and 156 anaerobes), for an average of 6.6 per specimen. The most prevalent anaerobes recovered were Prevotella spp. (34%), while streptococci comprised 44% of all aerobic organisms, over half of which were in the "Streptococcus milleri" group, particularly S. anginosus. The study demonstrated that the pathogens in human bite infections differ considerably from those present in animal bites.     

Maternal effects in human cleft lip and palate.

To look for a persistent maternal effect of CL(P) and CP, 8,000 pedigrees were screened for half sibships, and data were pooled from 16 investigators. After excluding known genetic or cytogenetic diagnoses from the probands with facial clefts, a recurrence risk of .011 was obtained for CL(P) based upon 342 maternal half sibs. This was nearly identical to the risk of .014 based upon 210 paternal half sibs. CP proband frequencies of .004 for maternal half sibs and .009 for the paternal counterparts were also found. The lack of significant maternal effects in this data supports previously reported data from twin studies and from interracial crosses from Hawaii. The lack of maternal effect in human CL(P) and CP is in contrast to genetic data on clefting in mice.     

Gene losses during human origins

Pseudogenization is a widespread phenomenon in genome evolution, and it has been proposed to serve as an engine of evolutionary change, especially during human origins (the “less-is-more” hypothesis). However, there has been no comprehensive analysis of human-specific pseudogenes. Furthermore, it is unclear whether pseudogenization itself can be selectively favored and thus play an active role in human evolution. Here we conduct a comparative genomic analysis and a literature survey to identify 80 nonprocessed pseudogenes that were inactivated in the human lineage after its separation from the chimpanzee lineage. Many functions are involved among these genes, with chemoreception and immune response being outstandingly overrepresented, suggesting potential species-specific features in these aspects of human physiology. To explore the possibility of adaptive pseudogenization, we focus on CASPASE12, a cysteinyl aspartate proteinase participating in inflammatory and innate immune response to endotoxins. We provide population genetic evidence that the nearly complete fixation of a null allele at CASPASE12 has been driven by positive selection, probably because the null allele confers protection from severe sepsis. We estimate that the selective advantage of the null allele is about 0.9% and the pseudogenization started shortly before the out-of-Africa migration of modern humans. Interestingly, two other genes related to sepsis were also pseudogenized in humans, possibly by selection. These adaptive gene losses might have occurred because of changes in our environment or genetic background that altered the threat from or response to sepsis. The identification and analysis of human-specific pseudogenes open the door for understanding the roles of gene losses in human origins, and the demonstration that gene loss itself can be adaptive supports and extends the “less-is-more” hypothesis.     

Allelic losses in mutations at the aprt locus of human lymphoblastoid cells.

We analyzed the nature of mutations at the autosomal locus coding for adenine phosphoribosyltransferase (aprt) in human cells to elucidate the process(es) governing mutagenesis at autosomal loci. A human lymphoblastoid cell line, WR10, was found to be heterozygous for mutated allele at the aprt locus, and was used for mutation analyses. By the use of a restriction fragment length polymorphism associated with the aprt locus in WR10 cells, the molecular characteristics of mutations arising spontaneously or induced by gamma-rays were investigated. Eighty-five percent (22/26) of the spontaneous mutant clones and 93% (64/69) of the gamma-ray-induced mutant clones resulted from loss of one of the two aprt alleles. Determination of the dosage of aprt genes in those mutants with allelic losses revealed that approximately half of them retained two copies of the mutated allele. These data suggest that the mutational events leading to APRT deficiency are analogous to those reported for tumor suppressor genes in malignancies.