Biomedical subjects

C S Williams

Publications and source records attributed to C S Williams.

At least 109 records · Page 6Linked to original sources

PubMed1993

Autogenous flexor-tendon grafts. A biomechanical and morphological study in dogs.

Intrasynovial and extrasynovial donor autogenous flexor-tendon grafts were placed in the synovial sheaths of the medial and lateral digits of the forepaw in twenty dogs (forty tendons). Postoperatively, the dogs were managed with early, controlled, passive mobilization. Histological and ultrastructural evaluations were carried out at ten days, three weeks, and six weeks, and biomechanical analyses were performed at three and six weeks. The intrasynovial and extrasynovial tendon grafts showed different healing processes histologically. The extrasynovial tendon grafts healed with early ingrowth of peripheral adhesions, which appeared to become larger and more dense over time. These grafts exhibited decreased cellularity and early neovascularization at ten days, and there was evidence of progressive revascularization and cellular repopulation at three and six weeks. In contrast, the intrasynovial tendon grafts demonstrated minimum adhesions, and both cellularity and collagen organization were normal at each time-interval. The intrasynovial grafts had significantly more angular rotation at the proximal interphalangeal joint at three and six weeks than did the extrasynovial grafts (p < 0.05).

Animals↗

PubMed1993

F-16 pilot experience with combat ejections during the Persian Gulf War.

Most experience with ejections from modern fighter aircraft has occurred outside of true combat operations. During Operation Desert Storm, the 401st Fighter Wing, Torrejon Air Base, Spain, lost four F-16C aircraft while on combat missions, with all four pilots ejecting safely. Since the circumstances of a combat vs. peacetime ejection are likely different and many combat mishaps and ejections cannot be extensively investigated (three out of these four), a questionnaire was developed to recall and review pilot ejection experiences. Questions ranged from recalling the parameters of egress to conscious recollections of the event and assessment of how well the system worked. Each of the four ejections occurred under different parameters, and no one suffered significant injury. Two of the ejections occurred at high altitude, previously rare in the F-16. This was one of the first times that experience was obtained with the F-16's ACES-II egress system under combat operations and, in the experience of these four pilots, the system was life-saving in combat. Finally, the overall ejection survival rate for U.S. Air Force fighter/attack combat ejections during Operation Desert Storm was similar to the peacetime rate. It is the author's hypothesis that the reason for this may correlate with a quicker, more predetermined decision to eject from an aircraft disabled by combat fire.

Aerospace Medicine↗

PubMed1993

Vascularity of the lunate. Anatomic studies and implications for the development of osteonecrosis.

Osteonecrosis of the lunate is well established as the pathologic entity underlying the clinical condition known as Kienböck's disease. Consequently, the extraosseous and intraosseous blood supplies to the lunate have been well studied. A series of three palmar and three dorsal arterial arches provide a consistent volar supply to the lunate, and a frequent, but inconsistent, dorsal supply. Volar and dorsal foramina each generally contribute one to two vessels to a volar and dorsal intraosseous arterial network. The dorsal and volar arterial systems anastomose distal to the midline of the lunate; however, in as many as 7.5% of lunates, no anastomosis my be present. Between 7% and 26% of lunates may lack either a volar or dorsal arterial supply. These findings have significant implications regarding possible mechanisms for the development of osteonecrosis and the treatment of Kienböck's disease.

Hand↗

PubMed1993

[The painful ulno-carpal joint. Diagnosis and therapy].

The ulnocarpal joint plays a critical role in hand and wrist function. It serves as part of forearm rotation as well as part of the carpal kinematics. The joint is comprised of the distal radio-ulnar articulation, triangular fibrocartilage complex, lunate, triquetrum, hamate, and pisiform, and the intra and extracapsular ligamentous and soft tissue constraints. Traumatic disruptions as well as chronic inflammatory conditions are commonplace. In addition to standard radiographs, arthrography, CT scanning, and MRI studies prove useful. Wrist arthroscopy is becoming of increasing importance in this region of the wrist. Ulnar impaction syndrome may occur associated with malunion of distal radius fracture, ulna positive variance, or chronic TFCC tears. Osteotomy of the distal radius or ulnar shortening osteotomy should be considered. Instability of the distal ulna can be treated with tenodesis procedures, hemi-resection arthroplasty, matched ulna resection or the Sauvé-Kapandji procedure.

Biomechanical Phenomena↗

PubMed1993

A comparison of the perioperative morbidity in total joint arthroplasty in the obese and nonobese patient.

The goal of this study was to determine if obesity is a risk factor for total joint arthroplasty. This was a retrospective review of 130 patients treated with either primary total hip arthroplasty or primary total knee arthroplasty during a two-year period (154 consecutive arthroplasties). The patients were placed in the nonobese or obese group. Obesity was defined as 20% above ideal weight for height, based on life insurance tables. There were 51 in the nonobese groups and 103 in the obese group. Charts were reviewed for a number of factors associated with postoperative complications. Operative time, intravenous fluids administered, and total blood loss were found to be slightly higher in the obese group. Only the difference in operative time proved statistically significant, however. The hospitalization time, number of days with a fever, number of transfusions, preoperative and postoperative hemoglobin levels, and days requiring intramuscular narcotics were very similar between the two groups. There were 0.29 minor complications per nonobese patient, but only 0.22 per obese patient. Major complications were encountered 0.22 times per nonobese patient and 0.10 times per obese patient. The patient is not necessarily at a higher risk for peroperative complications in total joint arthroplasty. The longevity of the implant in the obese patient was not determined in this perioperative study.

Aged↗

PubMed1993

Genomic plasticity of the Lucké renal carcinoma: a review.

The differentiation potential of the Lucké renal carcinoma of the northern leopard frog, Rana pipiens, can be characterized by the nuclear transplantation procedure. Transplantation of tumor nuclei into activated and enucleated ova results, in the best of cases, in swimming larvae which fail to feed. The larvae die in about 10 to 14 days. Rescue of tumor nuclear transplantation tadpole tissue, destined to die, has been accomplished by allografting fragments of that tissue to normal hosts. The allografts persist and differentiate a diversity of tissues which cannot be distinguished by histological analysis from allografted normal control tissue. Allografts are an imperfect mode of assay for histological competence because of the immune response of the host. Lymphocytes and eosinophils invade the grafts in about 40 days. The host immune response occurs in both experimental and control allografts. Consequently, we believe that added histogenetic potential exists in the genome of the Lucké renal carcinoma. We propose that unexpressed differentiative potential of the grafted tissue can be extracted by abrogation of the immune response of the host. A herpesvirus is the etiological agent of the Lucké renal carcinoma. We currently seek to detect viral DNA in tissue derived from tumor nuclear transplant embryos. The presence of the viral genetic material in normal mitotic progeny of Lucké tumor cells, if demonstrated, raises the question of the long-term stability of differentiated cells derived from a virus tumor. Alternatively, absence of viral DNA in the tumor nuclear transplant tissue would suggest that normal differentiation ensues after elimination of the oncogenic DNA from that tissue. Loss of viral DNA may prognosticate stable differentiation.

Animals↗

PubMed1992

Molecular basis of human hypertension: role of angiotensinogen.

Essential hypertension is a common human disease believed to result from the interplay of multiple genetic and environmental determinants. In genetic studies of two large panels of hypertensive sibships from widely separated geographical areas, we obtained evidence of genetic linkage between the angiotensinogen gene (AGT) and hypertension, demonstrated association of AGT molecular variants with the disease, and found significant differences in plasma concentrations of angiotensinogen among hypertensive subjects with different AGT genotypes. The corroboration and replication afforded by these results support the interpretation that molecular variants of AGT constitute inherited predispositions to essential hypertension in humans.

Adult↗

PubMed1992

Infant resuscitation is associated with an increased risk of left-handedness.

The etiology of left lateral preference is not well understood, but some studies have suggested that it can be caused by complications at birth. The authors used data from the Child Health and Development Study, a large prospective study of pregnancy and child development conducted 1959-1966 in the San Francisco Bay Area of California, to examine the association between specific birth stressors and hand and foot preference. The study population consisted of 6,968 5-year-olds with no severe congenital abnormalities, and the authors controlled for potential demographic confounders and familial left-handedness. Infants who required resuscitation after delivery or who were twins or triplets were about twice as likely to demonstrate left hand preference at age 5 years (odds ratio (OR) = 1.8, 95% confidence interval (CI) 1.3-2.5, and OR = 2.2, 95% CI 1.2-4.0, respectively). Left-footedness was also significantly associated with the same stressors. No other individual stresses were significantly associated with left-lateral preference, and a composite measure indicated only a weak association. Although males, blacks, and those with left-handed siblings are more likely to show left lateral preference, these variables do not confound the association between birth stress and left lateral preference. These results indicate that specific types of birth stress are strongly associated with left hand and foot preference; however, much of the left laterality in non-clinical populations remains unexplained.

Birth Injuries↗

PubMed1992

Comparative study of spermatogonial survival after x-ray exposure, high LET (HZE) irradiation or spaceflight.

Spermatogonial cell loss has been observed in rats flown on Space Lab 3, Cosmos 1887, Cosmos 2044 and in mice following irradiation with X-ray or with high energy (HZE) particle beams. Spermatogonial loss is determined by cell counting in maturation stage 6 seminiferous [correction of seminferous] tubules. With the exception of Iron, laboratory irradiation experiments (with mice) revealed a similar pattern of spermatogonial loss proportional to the radiation dose at levels less than 0.1 Gy. Helium and Argon irradiation resulted in a 5% loss of spermatogonia after only 0.01 Gy exposure. However, significant spermatogonial loss (45%) occured at this radiation level with Iron particle beams. The loss of spermatogonia during each space flight was less than 10% when compared to control (non-flight) animals. This loss, although small, was significant. Although radiation may be a contributing factor in the loss of spermatogonia during space flight, exposure levels, as determined by dosimetry, were not significant to account for the total cell loss observed.

Animals↗

PubMed1992

Angiogenesis in healing autogenous flexor-tendon grafts.

On the basis of recent evidence that flexor tendon grafts may heal without the ingrowth of vascular adhesions, eighteen autogenous donor tendons of intrasynovial and extrasynovial origin were transferred to the synovial sheaths in the forepaws of nine dogs, and controlled passive mobilization was instituted early in the postoperative period. The angiogenic responses of the tendon grafts were determined with perfusion studies with India ink followed by cleaing of the tissues with the Spalteholz technique at two, four, and six weeks. A consistent pattern of neovascularization was noted in the donor tendons of extrasynovial origin. Vascular adhesions arising from the flexor digitorum superficialis and the tendon sheath enveloped the tendon grafts by two weeks. By six weeks, the vascularity of the tendon grafts of extrasynovial origin appeared completely integrated with that of the surrounding tissues. Examination of cross sections revealed that the segments of tendon had been completely vascularized by obliquely oriented intratendinous vessels. In contrast, the flexor tendon grafts of intrasynovial origin healed without ingrowth of vascular adhesions. Primary intrinsic neovascularization took place from the proximal and, to a lesser extent, distal sites of the sutures. Examination of cross sections revealed vessels extending through the surface layer of the tendon graft, with small vessels penetrating the interior of the tendons at regular intervals.

Animals↗

PubMed1991

Regional differences in the morphology of the goat epididymis: a light microscopic and ultrastructural study.

The goat epididymis, based on morphological differences, was divided into five regions; regions I and II, and the proximal part of region III constituted the head; the distal part of region III and region IV, the body; and region V, the tail. The epithelium of all regions contained principal and basal epithelial cells and intraepithelial lymphocytes and macrophages. In addition, regions II to IV also contained a few apical cells. Clear cells were absent. The epithelium varied in height from the tallest in region I (88 +/- 33 microns) to the shortest in region V (38 +/- 5 microns). Conversely, the luminal diameter, thickness of smooth muscle wall, and luminal sperm concentration were highest in region V. The irregular epithelial height of regions I and IV accounted for a stellate lumen in contrast to the oval lumen of the other regions. Whereas the lumen of region I contained only a few sperm, those of regions II, III, and IV were filled with sperm. Principal cells were the only cell type that showed striking cytological differences between regions. While they contained absorptive features (canaliculi, pinocytotic and coated vesicles, and subapical vacuoles) in all regions, the principal cells of region II were filled with large, heterogeneous vacuoles (up to 5 microns in diameter), suggesting that they may be preferentially involved in transporting and digesting particulate material. Besides absorptive features, principal cells of all regions contained morphological correlates of protein synthesis such as highly developed Golgi complexes in the supranuclear area and numerous cisternae of RER near the Golgi body and in the infranuclear cytoplasm. The cisternae of RER were more developed in region IV, and in some instances, they were distended with flocculent material resembling newly synthesized protein. Unlike the protein synthesizing organelles, principal cells of all regions lacked morphological correlates of steroid hormone synthesis. These results are compared with previously published data on the regional differences in the epididymis of other species, especially with those of the rat and the bull, in an effort to understand the significance of the epididymis in sperm maturation.

Animals↗

PubMed1991

Development and DNA polymerase activities in cultured preimplantation mouse embryos: comparison with embryos developed in vivo.

Embryos from superovulated female mice that developed in vitro from the two-cell stage were compared with in vivo embryos with respect to yield of blastocytes, number and types of cells, morphology in histologic section, and DNA polymerase activities. Significantly more embryos developed into blastocytes in vitro (93%) than in vivo (18%). Inner cell mass (ICM) cells comprised approximately 30% of total cells in late morula/early blastocyst stage embryos developed either in vitro or in vivo. However, the in vitro embryos developed approximately half the number of total cells as in vivo embryos, did not develop endoderm, and did not develop abembryonic trophoblast cells with morphologic characteristics of late preimplantation in vivo embryos. DNA-dependent DNA polymerase activities in in vitro embryos decreased in correspondence with the decrease in cell number resulting in per cell levels comparable to in vivo embryos. In contrast, the poly (A).oligo(dT)-dependent DNA polymerase activity was the same in embryos developing either in vitro or in vivo, indicating different regulatory mechanisms for the two enzyme activities. A variety of nutrients and growth factors in the culture medium did not increase cell numbers or DNA polymerase activities in embryos cultured for 3 days; extending the culture an additional 24 hours resulted in a loss of ICM cells and decreases in both DNA polymerase activities. These results show that the retarded growth of embryos in vitro is equally distributed between ICM and trophoblast, is not reversed by culture conditions that include serum growth factors, and is not due to decreased cellular levels of DNA polymerase activities.

Animals↗

PubMed1991

Concentrations of estrone sulfate in peripheral serum of pregnant goats: Relationships with gestation length, fetal number and the occurrence of fetal death in utero.

Blood sampling was initiated shortly after breeding and continued weekly through 60 to 72 days post breeding in 20 pregnant and 5 nonpregnant dairy goat does. In does not showing a return to estrus by 72 days, collection of blood was continued at 10- to 14-day intervals until 135 days post breeding. At parturition, the numbers of does delivering one, two, three, four or five kids was four, ten, three, two and one, respectively. Immunoreactive estrone sulfate (ES) was measured in serum by radioimmunoassay (RIA). In nonpregnant does, the mean+/-SD concentration of ES was 0.1+/-0.1 nmol/l (n=36 samples). At 40 to 50 days post breeding, ES concentrations increased dramatically in pregnant does. Statistically, does were classified as pregnant when serum ES increased and remained above 1.1 nmol/l (P<0.05). Serum ES in pregnant does peaked at 65 to 75 days of gestation, remained at a relative plateau through 120 days and then gradually increased for the remainder of the sampling schedule. There were positive correlations between serum ES and the number of kids born in sampling periods of 50 to 55 days and after 90 days of gestation (P<0.05). Fetal loss was documented in two does that were not included in the survey data. One doe delivered two normal kids and two mummified fetuses. Time-trend changes in ES were typical of a normal pregnancy. Another doe had a marked decrease in ES (below 0.8 nmol/l) in samples drawn on Days 94 and 108 of gestation while luteal concentrations of progesterone were maintained. This doe delivered one weak, depressed kid, one stillborn kid and a decomposed fetus at the expected time for parturition.

Journal Article↗

PubMed1991

Experience of tuberculosis in immigrants from South East Asia--implications for the imminent lease back of Hong Kong.

We have undertaken a retrospective survey of patients of South East Asian ethnic origin (SEA), presenting with tuberculosis (between 1980 and 1989) while resident in the Liverpool district. Of 708 notifications in the 10-year period, 42 (6%) were SEA patients mainly from Hong Kong or mainland China. A total of 22 (52%) of the SEA patients presented with an extrapulmonary site of disease. Drug resistance was present in 11% of those for whom sensitivity results were available. Rates of disease in Hong Kong are similar to those seen in the Indian Subcontinent (ISC) population in the U.K. With the expected immigration of Hong Kong Chinese and possibly other SEA individuals to the U.K. as a result of the lease back of Hong Kong in 1997, all clinicians must be alerted to the possibility of tuberculosis whenever these individuals present with disease. The high incidence of extra pulmonary disease in SEA immigrants is striking and similar to that seen in the ISC population.

Adolescent↗

PubMed1990

Routine sheep and goat procedures.

Techniques involved in handling, restraint, sampling, identification, teat examination, and condition scoring are described. Procedures involved in foot trimming, docking, castrating, dosing, dehorning, descenting, dewattling, and giving injections are discussed. Care of the newborn is described.

Animal Husbandry↗

PubMed1990

Effects of spaceflight on the spermatogonial population of rat seminiferous epithelium.

Testes from rats flown on Cosmos 1887 were compared with vivarium control and synchronous control samples. The mean weights of flight testes, normalized for weight per 100 g, were 6.4% less when compared with the vivarium controls. Counts of spermatogonia from tissue sections (seminiferous tubules in maturation stage 6) from five animals in each group revealed 4% fewer spermatogonia in flight testes compared with synchronous controls and 11% fewer spermatogonia in flight samples compared with vivarium controls.

Animals↗

PubMed1989

Correlations of dihydropyrimidine dehydrogenase, thymidine phosphorylase and thymidine kinase activities in strongly and weakly malignant cultured murine neuroblastoma cells.

The C-1300 neuroblastoma tumor which arises spontaneously in the A/J mouse has been maintained in this mouse strain. Two different cell populations have been recognized in cultured C-1300 mouse neuroblastoma (MNB): (1) round, "neuroblast-like" cells, growing in suspension (poorly attached), that have a highly malignant behavior when injected into the A/J mouse (T1 cells); and (2) flat, "epithelioid" cells that attach well to surfaces and show low malignancy towards the inoculated animals (T2 cells). The specific activities of the pyrimidine metabolizing enzymes thymidine phosphorylase (TP), dihydropyrimidine dehydrogenase (DPD) and thymidine kinase (TK) were examined in both MNB cell lines by a new radiochromatographic method. Enzymatic activities of TP and DPD in the cytosols of T2 (weakly malignant) cells were up to 15 times higher than those of T1 (strongly malignant) cells, whereas the mean TP/DPD activity ratio was 16 in either cell line. TP and DPD activity levels increased with time of growth in culture in T2 cells while no such increase was seen in the T1 cells. Maximal TK activity was similar in both cell lines but dropped more rapidly in the T2 cells as cell densities increased. The enzymatic activity levels of TP and DPD but not of TK correlated inversely with neoplastic expression of MNB cells. The observed patterns of pyrimidine metabolizing enzymes in MNB cells could result in an increased thymidine pool in T1 cells whenever TK activity is suppressed, whereas such conditions would favor the generation of thymine in the T2 cells.

Animals↗

PubMed1988

The ductuli efferentes of the goat: a morphological study.

The morphology of the ductuli efferentes of the goat was compared with that of other animal species, especially with that of the bull. Both in the goat and in the bull, it forms a slightly brownish, bulbous mass of highly convoluted ductules (18-19 in the goat, 13-16 in the bull) that occupies approximately one third of the first limb of the caput epididymidis. The epithelium consists of two major cell types, ciliated and nonciliated, and a few intraepithelial lymphocytes and macrophages. The nonciliated cells can be further divided into three types: type II cells are characterized by specific granules that are dense, mostly homogeneous, eosinophilic, osmiophilic, and positive to periodic acid-Schiff (PAS) staining; type III cells are characterized by specific vacuoles that appear empty and do not stain with PAS, eosin, or osmium; type I cells lack both granules and vacuoles. These morphological, histochemical, and tinctorial differences observed among nonciliated cell types suggest that they are probably independent cell types rather than functional stages of one cell type. All three cell types are endowed with absorptive features such as microvilli, pinocytotic vesicles, and subapical vacuoles, but a higher differentiation of these features in type III cells suggests their greater role in the absorption of testicular fluid. Whether granules of type II cells and vacuoles of type III cells are absorptive and/or secretory remains unresolved from the available data. However, some circumstantial evidence, as presented in the discussion, supports the latter possibility.

Animals↗