Biomedical subjects
P Campbell
Publications and source records attributed to P Campbell.
Free microvascular tissue transfer in Newcastle upon Tyne.
One hundred and eleven cases of free tissue transfer were reviewed to assess the indications for, and results of, such procedures. More than 90% of cases were seen after treatment of tumour or trauma, with the most utilized flaps being the radial forearm, jejunum and latissimus dorsi. Fifteen per cent of cases required re-exploration of the anastomosis, of which more than 75% were salvaged. Haematoma formation and venous thrombosis were the commonest problems and were more successfully treated than arterial occlusion. The overall success rate was 92%. Free microvascular tissue transfer is a useful and reliable technique, especially in the management of head and neck tumours and limb trauma. The most important factors relating to flap survival are the experience of the surgical team and the integrity of the anastomosis.
Mechanism and clinical significance of wear debris-induced osteolysis.
Loosening of joint replacement components is often multifactorial. The quality of initial fixation is very important to the outcome of the arthroplasty and is often a factor in short-term and long-term failure. This paper discusses another important factor of implant loosening, namely wear debris induced osteolysis. Macrophages activated by the phagocytosis of particulate wear debris are the key cells in this process, which can potentially occur in any implant system regardless of implant design or fixation mode. This is because each implant system creates wear debris from the articulating surfaces and the interfaces. The clinical consequences of wear debris cover a broad spectrum from radiolucencies to massive osteolysis and implant failure. For this reason, the reduction of wear debris should be a primary goal of orthopedic research in the future.
Two forms of ring 13 in a child with rhabdomyosarcoma.
Mosaicism for two forms of ring 13 was found in a child with embryonal rhabdomyosarcoma of the bladder, minor anomalies, and developmental delay. Her chromosome constitution was 46,XX,r(13)(p11q34)/46,XX,r del(13)(p11q14). Both cell lines were present in lymphocytes and fibroblasts. The cell line with the smaller ring chromosome predominated in both tissues. The child's manifestations reflect the presence of both cell lines.
Localization of boar sperm proacrosin during spermatogenesis and during sperm maturation in the epididymis.
The localization of proacrosin was determined by using colloidal gold labeling and electron microscopy of boar germ cells during spermiogenesis to post-ejaculation. Proacrosin was first localized in round spermatids during the Golgi phase of spermiogenesis; it was associated with the electron-dense granule, or acrosomal granule that was conspicuous within the acrosome. It remained within the acrosomal granule during the cap and acrosome phases of spermiogenesis. At these stages, there was no apparent association of the proacrosin molecule with the acrosomal membranes. During the maturation phase of spermiogenesis, proacrosin was seen to become dispersed into all regions of the acrosome except the equatorial segment. When sperm from different segments of the epididymis and ejaculated sperm were examined, localization was observed throughout the acrosome except for the equatorial segment. Here proacrosin appeared to be localized on both the inner and outer acrosomal membranes as well as with the acrosomal matrix, although further studies are required to verify the membrane localization. No labeling was seen on the plasma membrane. These data suggest that the synthesis and movement of proacrosin to sites in the acrosome are controlled by an as yet unknown process. The absence of proacrosin on the plasma membrane of mature ejaculated sperm makes it unlikely that this enzyme plays a role in sperm-zona adhesion prior to capacitation.
Two-dimensional polyacrylamide gel electrophoresis characterization of APz, a sperm protein involved in zona binding in the pig and evidence for its binding to specific zona glycoproteins.
A boar sperm integral plasma membrane protein (APz) involved in the adhesion of uncapacitated and capacitated sperm to the porcine zona pellucida (ZP) has been characterized by two-dimensional polyacrylamide gel electrophoresis (PAGE) and tested for its ability to bind to various zona glycopeptides. APz shows microheterogeneity and focuses over a wide pH range, with predominant forms focusing above pH 7. The protein, when excised from nonreducing polyacrylamide gels, inhibited sperm-egg binding and bound heat-solubilized zonae preventing these zonae from blocking sperm binding to eggs. In an indirect assay, a polyclonal monovalent antibody, which blocks sperm-egg binding and which is absorbed by APz, was used to determine the ability of zona glycopeptides to prevent the sperm-egg blocking activity of the antibody from being absorbed by intact sperm. When whole heat-solubilized ZP was added to sperm at doses that block sperm-egg binding and the excess ZP was removed, the sperm-egg blocking activity of the antibody was not absorbed by these sperm, and antibody-containing supernatants blocked the binding of untreated sperm to eggs as effectively as antibody that was not mixed with fresh sperm. When alpha ZP3 was used in the same manner, sperm-egg blocking activity again was not absorbed by antibody-treated cells. Beta ZP3, however, failed to block sperm-egg binding and failed to absorb the sperm-egg blocking activity of the antibody. These findings support the argument that the action of APz is physiologically significant and involves specific binding sites on the ZP3 component of the ZP.
Ion channels in boar sperm plasma membranes: characterization of a cation selective channel.
Plasma membranes isolated from cauda epididymal and ejaculated boar sperm were inserted into planar lipid bilayers and examined for the presence of ion channels. Channel fusion was frequently observed; the most prominent was a nonselective cation channel which conducted K, Na, Cs, Ca, and Ba. Channel opening did not show a strict dependence on voltage but was partially blocked by verapamil, nitrendipine, and ruthenium red. A channel with these characteristics was observed when plasma membranes were isolated by high-pressure nitrogen cavitation (650 psi, 78% sperm head plasma membranes) or at very low nitrogen pressures (50 psi, 90% sperm head plasma membranes), suggesting that this channel may be present in the plasma membrane overlying the sperm head.
Electron microscopic evidence of acarine infestation of the eyelid margin.
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N-acetylglucosamine-6-phosphate deacetylase in hepatocytes, Kupffer cells and sinusoidal endothelial cells from rat liver.
The activity of N-acetylglucosamine-6-phosphate deacetylase, a key enzyme in the pathway of N-acetylglucosamine catabolism, was measured in hepatocytes, Kupffer cells and sinusoidal endothelial cells from rat liver and cultured human skin fibroblasts. Kupffer cells and endothelial cells had similar high levels of deacetylase activity that were more than twice the level observed in fibroblasts. In contrast, hepatocytes had extremely low activity (several hundredfold less than Kupffer cells and endothelial cells). A major implication of deacetylase deficiency in hepatocytes is that N-acetylglucosamine generated as a result of the catabolism of complex carbohydrates in these cells cannot enter glycolysis and must be largely reused for the synthesis of plasma glycoproteins and other N-acetylglucosamine-containing macromolecules.
Multiple abnormalities in a child with partial duplications of 10p and 13q from a 3:1 segregation of a maternal t(10;13) translocation.
Partial duplications of 10p and 13q in association with partial deletions of other chromosome segments have been variously reported. We describe here a female child with multiple congenital abnormalities and combined partial duplications of 10p and 13q resulting from a 3:1 segregation of a maternal t(10;13)(p13;q22). In comparing the phenotypic features of the two chromosome imbalances, the expression of features typical of partial duplication 10p appeared more pronounced.
Physician-management relationships at HCA: a case study.
The questions of whether Hospital Corporation of America (HCA), a for-profit hospital company, fostered an environment detrimental to the physician-patient relationship during the period of implementation of the Medicare Prospective Payment System (PPS) was explored. The transition to PPS provided an opportunity to evaluate whether hospital ownership differences affected responses to a payment system which encouraged institutional intervention in the practice of medicine. A case study approach was used to observe the influence of the then largest for-profit hospital corporation upon physicians' medical practice in four owned hospitals. Findings indicated that HCA hospital managers were most directly influenced by the local competitive environment and their own personal agendas in responding to PPS incentives. Corporate influence actually softened payment system incentives to intervene in medical practice by providing a generous supply of capital, and by fostering a corporate culture conducive to cooperative relationships with physicians. Better public understanding of the determinants of hospital behavior is needed to preserve or enhance important social goals such as the physician-patient relationship; easily measurable characteristics such as ownership or bed size explain little about hospital behavior or motivation.
Reye's syndrome: a case control study of medication use and associated viruses in Australia.
The records of 49 cases of Reye's syndrome at three pediatric hospitals in Australia are compared with 94 controls. The diagnosis of Reye's syndrome was confirmed pathologically in 42 of 49 cases (86%). Aspirin or salicylate ingestion occurred in only 4 (8%), and paracetamol (acetaminophen) ingestion in 12 (24%) (P greater than 0.05 by chi-square analysis). Of the controls, 3 (3%) had taken aspirin and 39 (41%) had taken paracetamol. Associated viruses included paramyxoviruses, picornaviruses, reoviruses, adenoviruses, and occasional varicella-zoster (herpesvirus). No influenza A or B viruses were recovered from any patient. This case control study of Reye's syndrome in Australia confirmed a lack of association between aspirin ingestion and the development of Reye's syndrome.
Arthrodesis of the ankle with modified distraction-compression and bone-grafting.
A modification of the technique of Chuinard and Peterson for distraction-compression arthrodesis of the ankle was used in twelve patients, whose ages ranged from ten to seventy-one years. This modified technique allows positioning that is better for function and it makes fusion more certain. It also offers the advantages of the original technique--that is, it preserves the potential for growth of the distal tibial and fibular physes and it maintains the height of the malleolus and foot. The duration of follow-up averaged four years and three months. The preoperative diagnoses were degenerative arthritis, poliomyelitis, talipes equinovarus, and myelodysplasia. Solid fusion was achieved in all patients, although one patient needed reoperation before fusion was achieved. The time to fusion averaged eleven months (range, three to sixteen months). The functional result was good in all patients.
Histological analysis of a central tarsal implant in a racing greyhound.
The hock of a greyhound containing a titanium alloy central tarsal replacement was examined histologically. The animal had raced competitively 43 times before retirement. The examination showed that the adaptation and encapsulation of the implant by the surrounding bones, together with the excellent purchase of the screw into the fourth tarsal bone, had maintained the implant in excellent position during vigorous load-bearing. There was no histopathological evidence to suggest that the fixation of the implant was failing. The results provide evidence for the value of titanium alloy implants as a central tarsal replacement in greyhounds with type V fractures, and as a feasible alternative to euthanasia.
Enzymic pathways of hyaluronan catabolism.
The enzymic degradation of hyaluronan in mammalian tissues takes place in two phases, encompassing breakdown of the polysaccharide to its monosaccharide constituents and subsequent utilization of the monosaccharide products. Degradation to the monosaccharide components is effected by the concerted action of three enzymes, hyaluronidase, beta-D-glucuronidase and beta-N-acetyl-D-hexosaminidase. The relative contributions of hyaluronidase and the two exoglycosidases to the physiological catabolism of hyaluronan are not yet known but consideration of the kinetic properties of the three enzymes clearly indicates that hyaluronidase is best suited for the initial attack on the polysaccharide, inasmuch as its Km for hyaluronan is 1000- to 10,000-fold lower than that estimated for beta-D-glucuronidase. Recent investigations in the authors' laboratories have been focused on the catabolism of hyaluronan and other complex carbohydrates in liver, since the sinusoidal endothelial cells in this organ are the main sites for degradation of circulating hyaluronan. Assay of ten lysosomal hydrolases in isolated rat liver cells showed considerably higher activities in Kupffer cells and endothelial cells than in hepatocytes for nine of the enzymes, including beta-D-glucuronidase and beta-N-acetyl-D-hexosaminidase. The activity of N-acetylglucosamine-6-phosphate deacetylase, a key enzyme in the metabolism of the N-acetylglucosamine released by the lysosomal degradation of hyaluronan and other complex carbohydrates, has also been determined. High deacetylase activities were observed in both Kupffer cells and endothelial cells but, surprisingly, virtually no activity was detected in hepatocytes. This finding implies that N-acetylglucosamine cannot be degraded in hepatocytes and must be largely reutilized in the synthesis of new macromolecules. Further studies of the enzymes involved in hyaluronan degradation and N-acetylglucosamine utilization in the liver are under way.
Changes in aldehyde dehydrogenase during rat urinary bladder carcinogenesis.
We have reported that normal rat urinary bladder possesses significant amounts of an aldehyde dehydrogenase (class 3 ALDH) expressed during hepatocarcinogenesis, but not detectable in normal liver. Changes in expression of both liver and bladder ALDH during N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN)-induced bladder carcinogenesis were studied. The ALDH phenotype was determined at intervals over 42 weeks by histochemical analysis, total ALDH activity assays and gel electrophoresis using propionaldehyde and NAD (P-NAD) which characterizes class 1 and 2 ALDH, or benzaldehyde and NADP (B-NADP) to determine class 3 ALDH. By total activity assays and gel electrophoresis, there was a significant decrease in bladder class 3 ALDH activity during weeks 5-15. Histochemical analysis clearly demonstrates changes in ALDH early in neoplastic development. Intense staining with B-NADP in regions of hyperplasia was first detectable at week 10. Staining in hyperplastic regions was accompanied by a significant decrease in ADLH in neighboring, apparently normal urothelium. As the urothelium became more abnormal, class 3 ALDH activity increased. By week 25, the bladder class 3 ALDH activity of BBN-treated animals was 2 times greater than the control group class 3 ALDH activity. Histochemically, all papillomas and carcinomas examined possessed class 3 ALDH. However, staining was heterogeneous within the lesions. Bladder neoplasm class 3 ALDH specific activity was greater than control group class 3 ALDH activity in 70% of papillomas and carcinomas. These results suggest events may be occurring in bladder similar to those in liver which alter expression of aldehyde dehydrogenase during carcinogenesis.
Horner's syndrome caused by an intercostal chest drain.
Horner's syndrome occurred in a young woman as a complication of the treatment of a traumatic pneumothorax with an intercostal drain. The nerve damage probably occurred when the lung had fully re-expanded, pressing the tip of the intercostal drain, lying at the apex of the pleural cavity, on to the sympathetic chain.