Biomedical subjects
Publications and source records attributed to L A Gordon.
Symptomatic biliary tract disease in the pregnant patient has always been problematical. The advent and widespread application of laparoscopic cholecystectomy has led to a re-evaluation of the role of surgery in this clinical situation. We report on the use of laparoscopic cholecystectomy on a patient in the first trimester of pregnancy.
Benign abdominal cystic tumors are rare. They include retroperitoneal, mesenteric, and omental cysts. Most of these lesions present with vague abdominal pain and nausea. Less commonly they will present with bowel obstruction due to external compression. The diagnosis of these tumors is by abdominal ultrasound or computed tomography. Surgical enucleation is the treatment of choice. Laparoscopic surgical techniques are replacing or complimenting open abdominal surgical procedures. As the indications for these techniques increase, newer applications will arise. Presented here is a case of laparoscopic excision of a mesenteric cyst.
Fluorescence in situ hybridization was used to determine the spatial distribution of chromatin in zygote pronuclei. A hybrid system involving golden hamster eggs and individual human sperm permitted use of DNA probes specific for the entire human chromosome 4, for the heterochromatic region on the long arm of the human Y chromosome and for unique DNA sequences on human chromosome 19. Chromosome 4 occupied a circumscribed domain in the pronuclei, similar to findings in somatic interphases. Unlike the situation in somatic interphases, the Y heterochromatin was extended throughout the first cell cycle. Pronuclear chromatin was extended 3- to 4-fold compared to somatic interphase chromatin. The extended pronuclear chromatin conformation is likely to affect a zygote's susceptibility to environmental hazards.
Fluorescence in situ hybridization was used to establish the order of, and to estimate genomic distances among, members of the carcinoembryonic antigen (CEA) and pregnancy-specific glycoprotein (PSG) subgroups on chromosome 19. Fluorescence in situ hybridization to metaphase chromosomes localized the PSG subgroup telomeric to the CEA subgroup. Cosmid clones containing sequences for individual genes in the CEA and PSG subgroups were also hybridized to human sperm pronuclear and somatic interphase nuclear chromatin targets. The mapping results lead to the gene order cen-CGM7-CEA-NCA-CGM1-BGP-CGM9-CGM8-PSG-te l. The genomic distances between selected pairs of gene family members were estimated from the physical distances between hybridization sites measured in pronuclei. The CEA-PSG gene family region is estimated to span 1.1 to 1.2 Mb.
Various types of DNA probes, such as total genomic DNA, repetitive sequences, unique sequences, and composites of chromosome-specific DNA probes, can be used with fluorescence in situ hybridization (FISH) techniques to address research questions having to do with localization, mapping, and distribution of DNA in situ. FISH involves the formation of a heteroduplex between such DNA probes and chromatin targets on a microscope slide, which can be visualized with fluorescent reporter molecules. Three chromatin targets--metaphase chromosomes, somatic interphases, and zygote interphases--offer increasingly extended states of chromatin which can be strategically selected, individually or in combination, to address specific research questions of interest.
After fusion with an egg, the haploid genome of a mammalian sperm expands from a volume of a few cubic microns to a volume of several thousand cubic microns in a fully developed zygote pronucleus. Using fluorescent in situ hybridization we studied two aspects of the chromatin organization of the sperm-derived genome during this process in a model system involving fusion of human sperm with hamster eggs. We found that (a) from the beginning of sperm head decondensation to early pronuclear stages, the hybridization signal of a probe targeted to the satellite III heterochromatin of chromosome 1 appeared as an irregularly shaped domain. In fully developed pronuclei, the signal became a fiber as much as 20-fold more extended compared with interphase somatic nuclei. The signal appeared as a string of non-uniformly distributed "beads" with interspersed gaps. A similar spatial distribution and appearance recurred after the first cleavage division. (b) Male- and female-derived genomes assembled non-randomly on the first mitotic spindle, and continued to be sequestered from each other in the nuclei of two-cell stages.
The authors' initial experience with transcystic duct and direct laparoscopic approaches to the exploration of the common bile duct is reported. The technique requires standard laparoscopic equipment, specialized endoscopes, and instruments developed for urologic stone manipulations. After cholangiography confirmed the presence of common bile duct stones, common duct stone extraction was performed in 16 selected patients age 20-88 years. Stones ranged in size from 1 mm to 30 mm and they were unsuspected in 60% of the patients. Five patients had normal liver function tests and only 3 had clinical evidence of jaundice. Ductal exploration and stone extraction was successful in all 16 patients. One patient required a direct laparoscopic ductal exploration due to the presence of a common hepatic duct stone and the anatomy of the cystic duct. No major complications or deaths were observed in this series. Appropriately trained surgeons can safely and effectively perform laparoscopic common bile duct exploration and stone extraction in selected patients.
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Golden hamster eggs fused with human sperm were pulsed with bromodeoxyuridine to determine the timing of S-phase and the length of the first cell cycle in this hybrid cross. Fused eggs were fixed and pronuclei scored for incorporation of the thymidine analogue detected by indirect immunofluorescence. Although S-phase started synchronously 3-3.5 hr after coincubation of sperm and eggs, its duration was variable such that two-cell stages appeared at 16 hr while a proportion of pronuclei was still engaged in DNA synthesis. Unlike rodent sperm chromatin, human sperm chromatin was able to participate in DNA synthesis well before its maturation into a fully developed pronucleus. Human sperm chromatin appears able to function under conditions different in several respects from those in human eggs.
Types and frequencies of structural aberrations in human sperm and lymphocyte chromosomes from one donor were compared after in vitro irradiation with 100, 200, and 400 rad in order to determine if cells with dramatically different chromatin configurations are similarly affected and to investigate the feasibility of using lymphocytes as surrogates for germ cells in risk estimation. Sperm chromosomes were analyzed after fusion with eggs from the golden hamster. Total frequencies of induced aberrations were similar in the two cell types. However, the relative frequencies of rejoined lesions (dicentrics), compared with unrejoined lesions (chromosome breaks and acentric fragments), were different. At the three doses tested, a constant ratio of 5 dicentrics in lymphocytes for every dicentric in sperm was induced. Conversely, for every chromosome break or acentric fragment induced in lymphocytes, 1.7 such events were induced in sperm at the three doses tested.
Human sperm chromosome complements were examined to assess the possibility that the conceptions of two children with the same chromosomal defect, del(13)(q22q32), from chromosomally normal parents were the result of a paternal germ cell mosaicism. Analysis of 216 complements, both by quinacrine banding and by measuring the relative length of chromosome 13, showed no unusual subpopulation of 13s; this decreased the likelihood of a paternal origin of the deletion. Sperm chromosomal analysis is a useful adjunct to available techniques in clinical genetics. When counseling cases involving either structural or numerical de novo chromosome abnormality, it is of importance to discuss the possibility of germ cell line mosaicism as well as to offer prenatal diagnosis for subsequent pregnancies.
We have analyzed structural aberrations in 5,000 sperm chromosome complements obtained from 20 men over a 5-yr period by fusion of human sperm with hamster eggs. Detailed data are presented on 366 abnormal cells with 379 analyzable breakpoints. The frequency of cells with structural aberrations ranged from 1.9% to 14.5% among donors; this interindividual variability was statistically significant (p less than 0.0001). In contrast, repeat samples from individual men showed no significant variation over time. The number of sperm chromosome sets processed per hamster egg had no effect on the frequency with which structural aberrations occurred, nor were sperm chromosome abnormalities altered by varying capacitation or culture conditions. The spectrum of structural aberrations observed in human sperm chromosomes and a chi-square analysis of breakpoints based on DNA content are presented. Although human sperm chromosome abnormalities were visualized with a cross-species system, we believe that they represent an inherent, biologically significant phenomenon.
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A case is presented of a young adult with splenic hemorrhage secondary to infectious mononucleosis. The patient was managed successfully without surgery and has done well over the long term with progressive resolution of the hematoma on ultrasound. The implications of this case for the management of patients with this syndrome are discussed.
Human sperm that had been processed for Y-enrichment (male sex preselection) according to a currently favored albumin density gradient procedure were analyzed karyotypically for the proportion of X and Y chromosomes with the use of the human sperm/hamster egg system. This method allows direct inspection of haploid chromosome complements from human sperm. In 290 albumin-isolated sperm from six men, there were 57.2% X- and 42.8% Y-bearing chromosome complements; 201 unprocessed concurrent control sperm from five of the men had 50.2% X and 49.8% Y complements. The observed shift in sex chromosome ratio in processed samples, a decrease in Y-bearing sperm, was not statistically different from that of unprocessed controls (P = 0.13) but was significantly different when compared with the theoretic X/Y ratio of 50/50 (P = 0.016). A total of 3187 historical control karyotypes were also reviewed, with an overall sex chromosome ratio (X/Y) of 49.8/50.2. The control groups did not differ significantly from the expected 50/50. The Y-enrichment of processed sperm was not confirmed.
The chromosome constitutions of sperm selected for motility according to the swim-up technique were compared cytogenetically with those of sperm remaining in the semen with the use of the human sperm/hamster egg system, in which human sperm are fused with hamster eggs to give analyzable haploid chromosome complements. Three semen samples from one donor resulted in 153 chromosome complements from selected, highly motile sperm and 110 unselected, control complements. Four samples were donated by another man, from which 181 selected and 186 control complements were obtained. The frequencies of chromosomal aberrations recovered from the population selected for high motility and the unselected population were not statistically different from one another.
A questionnaire study of men in a wastewater treatment plant of a petroleum refinery showed twice the rate of fetal loss in the period during employment in the plant compared with the periods before and after. Questions regarding the interpretation of that study and continuing concern about reproductive risk prompted us to perform a cross sectional evaluation of sperm concentration and morphology. After adjustment for an abstinence period, the mean sperm concentration of the 74 unexposed men did not differ significantly from that of the 34 exposed men (79.9 million/cm3 v 68.2 million/cm3, p(1) = 0.16). The two groups also had a similar proportion of sperm with abnormal morphology (49.1% v 44.5%, p(1) = 0.94). This lack of association remained when degree of exposure, age, use of alcohol and marijuana, past illness or fever, use of baths or sauna, and history of urological problems were considered. These results are most consistent with the absence of sperm mediated reproductive problems.
Cytologic and histopathologic diagnoses were assessed independently without clinical details in 150 lesions from 112 consecutive patients. Nine of the lesions (6%) could not be evaluated cytologically because of unsatisfactory smears. Correct cytodiagnosis was obtained in 125 of 141 (89%) evaluable lesions. A solar keratosis with prominent basal cell hyperplasia was incorrectly assessed as a basal cell carcinoma (BCC). Five BCCs were misdiagnosed as squamous atypia, either because the smears were not representative or from inability to distinguish between pleomorphic BCC and severe squamous atypia. An incorrect cytologic diagnosis was thus made in 4% of lesions. Smears from ten lesions (7%) were reported as nondiagnostic for the same reasons. Cytologic diagnosis is simple, rapid, and accurate and is of value in the management of suspected cutaneous BCC.