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D M Sherman

Publications and source records attributed to D M Sherman.

At least 37 records · Page 2Linked to original sources
PubMed1990

Immunological characterization of the Prochlorothrix hollandica and Prochloron sp. chlorophyll a/b antenna proteins.

Polyclonal antibodies were prepared against the major antenna chlorophyll (Chl) a/b-binding protein from the prokaryote Prochlorothrix hollandica (Burger-Wiersma et al. (1986) Nature (Lond.) 320, 262-264). Immunoblotting experiments on Triton X-114 phase-partitioned P. hollandica thylakoids revealed that the antibody recognizes intrinsic membrane polypeptides of 33 and 30 kDa, and immunocytochemistry of P. hollandica thin sections showed that the antibody preferentially decorates the thylakoid. The antibody was immunopurified against a LacZ fusion protein produced in Escherichia coli by an immunopositive phage clone retrieved from a lambda ZAP expression library. This purified antibody crossreacted to both the 33 and 30 kDa polypeptides, indicating that these proteins are either structurally related products of different genes, or modified forms of the same gene product. Whereas immunological crossreactivity of Prochlorothrix antibody to the major LHC-II Chl a/b antenna of maize could not be detected, the immunopurified antibody reacted strongly to the major 34 kDa Chl a/b antenna protein from the prokaryote Prochloron sp. (Lewin (1975) Phycologia 14, 153-160). These data confirm the structural similarity of the prochlorophyte photosynthetic antenna systems.

Antibodies↗
PubMed1990

Morphological, developmental and immunohistochemical observations on the opossum pituitary with emphasis on the pars intermedia.

Development of the pituitary in Didelphis follows the general pattern of that described for most mammalian species. The dorsal region of a multichambered pituitary vesicle, which forms from Rathke's pouch, comes to lie adjacent to the presumptive infundibulum by the 10 1/2 d of gestation. The epithelial wall of this vesicle consists of spindle-shaped cells. The dorsal wall of the upper chamber of the pituitary vesicle forms the pars intermedia; the ventral wall of this chamber gives rise to cells of the pars distalis. Corticotropes, somatotropes, and lactotropes are seen in the presumptive adenohypophysis of the 11 1/2 d embryo. Gonadotropes and thyrotropes appear about 1 d later, shortly after birth. By the 2 postnatal week, the adult distribution of all 5 cell types within the pars distalis appears to have been established. The wall bounding the pituitary cleft in the adult represents an epithelial continuum limited by a basal lamina and corresponds to the upper chamber of the original pituitary vesicle. Ultrastructurally, the limiting walls of the pituitary cleft consists of stellate (marginal) cells, large, bulbous cells, and granulated cells. The latter correspond to the various endocrine cell types normally associated with the pars distalis. Non-granular folliculo-stellate cells also are observed within the epithelial cords of the pars distalis.

Aging↗
PubMed1990

[The antishock action of opiate antagonists].

In acute experiment on 86 adult rabbits with traumatic shock modelled according to Cannon, it was established that intravenous administration of Nalorphine at the doses of 0.5 and 2 mg/kg of weight at the early period of shock contributed to prolongation of lifetime of the majority of animals. In some of them, the small doses accelerated the occurrence of lethal outcome. In administration of 0.1 mg/kg of weight of Naloxone, almost all the animals survived. At the late period of shock, the effectiveness of these preparations is insufficient.

Animals↗
PubMed1990

Comparison of the complement-fixation and agar gel immunodiffusion tests for diagnosis of subclinical bovine paratuberculosis.

The performance of the serum complement fixation (CF) test was compared with that of a serum agar gel immunodiffusion (AGID) test on 74 subclinically infected and 154 uninfected cattle in 6 commercial midwestern dairy herds with Mycobacterium paratuberculosis infection and on 30 cattle in a herd that was free of infection. Infection status of cattle within herds was established by performance of a series of 3 or more fecal cultures and of ileocecal lymph node cultures of culled cattle. In cattle with subclinical infection detected by culturing, the sensitivity estimates of the CF and AGID tests were 10.8% (3.6% SE) and 18.9% (4.5% SE), respectively. In the cattle classified as disease free, the specificity estimates of the CF and AGID tests were 97.4% (1.3% SE) and 99.4% (0.6% SE), respectively. Neither set of estimates was significantly different. Negative test results obtained with the use of either test in apparently normal cattle from suspect herds should be interpreted with caution because both tests suffer from low sensitivities in subclinically infected animals. However, the AGID test may be more useful in regulatory situations in which the CF test is currently used because the AGID test is easier to perform and to interpret.

Animals↗
PubMed1989

DNA sequence and regulation of the gene (cbpA) encoding the 42-kilodalton cytoplasmic membrane carotenoprotein of the cyanobacterium Synechococcus sp. strain PCC 7942.

The gene (cbpA) coding for a carotenoid-binding protein of the cyanobacterium Synechococcus sp. strain PCC 7942 (Anacystis nidulans R2) has been cloned and sequenced. A polyclonal antibody against the protein was used to identify immunoreactive clones from a lambda gt11 expression library of Synechococcus strain PCC 7942. The initial positive clone (lambda gtAN42) contained a 0.9-kilobase (kb) chromosomal fragment, which was used to detect a larger chromosomal fragment from a lambda EMBL3 library. The lambda EMBL3 recombinant, lambda EM109, contained an 18-kb portion of the Synechococcus strain PCC 7942 chromosome. The open reading frame of cbpA encoded 450 amino acids which give rise to a protein of 49,113 daltons. The hydrophobicity plot indicates that the protein may have a 49-residue signal sequence which is cleaved to yield a mature protein of 43,709 daltons. The protein has been localized in the cytoplasmic membrane by biochemical procedures as well as by electron microscopic immunocytochemistry. Northern (RNA) blot analysis indicates that transcription of cbpA is tightly regulated by DNA topology, light intensity, and iron concentration. Transcription is greatly induced by growth under high light intensities and repressed during growth under iron-deficient conditions. The DNA gyrase inhibitor novobiocin specifically inhibited the light-induced transcription. In Northern blots, the gene-specific probe hybridized to two size classes of RNA, with lengths of 2.0 and 6.2 kb. Since cbpA appears to be a component of the 6.2-kb transcript, it is likely part of a larger operon.

Amino Acid Sequence↗
PubMed1989

Evaluation of the agar gel immunodiffusion test for diagnosis of subclinical paratuberculosis in cattle.

Concurrent bacteriologic culture of feces and agar gel immunodiffusion (AGID) testing was performed on all cows and bred heifers over 14 months old in 10 dairy herds during a 32-month period to determine the effectiveness of the AGID test for the detection of subclinical paratuberculosis. Herds were sampled 5 times and, when possible, culled animals were tested again at slaughter. During 5 herd-wide samplings, Mycobacterium paratuberculosis was isolated from 139 fecal specimens obtained from 109 cattle. Results of the AGID test were simultaneously positive 40 of 139 times (28.8%). Thirty-six of the 109 cattle (33.0%) determined to be infected had a positive AGID test result at some point during the 5 herd-wide samplings. When results of tests performed at time of slaughter were included, 117 cattle were identified as infected by culture methods; 55 of these (47.0%) were AGID test-positive at some point during the study. The upper limit of the maximal false-positive rate for the AGID test was 2.1%. On the basis of colony counts from cultures, subclinically infected cows shedding higher numbers of M paratuberculosis in their feces were more likely to have positive AGID test results (P less than 0.0001). In known infected cattle, neither the culture nor AGID test results were consistently positive on repeated testing. Of 48 official calfhood paratuberculosis vaccinates tested as adults, 3 had positive AGID test results and in 1 of these, M paratuberculosis was also isolated from the feces, indicating that the rate of false-positive AGID test results in calfhood vaccinates is low.

Animals↗
PubMed1989

[Therapeutic effect of nalorphine and naloxone in experimental traumatic shock].

In their acute experiments on 86 rabbits the authors have established that the intravenous administration of nalorphine and naloxone produces a marked therapeutic effect only during the early period of experimental traumatic shock. In most of the animals there was a reliable extension of the lifetime (nalorphine) and an increase in the survival rate (naloxone). In a lesser part of the animals the administration of nalorphine had no considerable influence on the outcomes. During the late period the therapeutic effect of these drugs has not yet been manifested. A conclusion has been made that the contradictory data in the literature concerning the effect of nalorphine and naloxone on the course of experimental traumatic shock seem to depend on the fact that they were administered at various stages of this pathologic process. It is pointed out that it is advisable to administer these drugs (especially naloxone) at the pre-hospital stage in the patients with traumatic shock.

Animals↗
PubMed1988

Cloning, nucleotide sequence, and mutagenesis of a gene (irpA) involved in iron-deficient growth of the cyanobacterium Synechococcus sp. strain PCC7942.

We describe the cloning and sequencing of a gene from the cyanobacterium Synechococcus sp. strain PCC7942, designated irpA (iron-regulated protein A), that encodes for a protein involved in iron acquisition or storage. Polyclonal antibodies raised against proteins which accumulate during iron-deficient growth were used as probes to isolate immunopositive clones from a lambda gt11 genomic expression library. The clone, designated lambda gtAN26, carried a 1.7-kilobase (kb) chromosomal DNA insert and was detected by cross-reactivity with antibody against a 36-kilodalton protein. It was possible to map a 20-kb portion of the chromosome with various DNA probes from lambda gt11 and lambda EMBL-3 clones, and Southern blot analysis revealed that the irpA gene was present in a single copy and localized within a 1.7-kb PstI fragment. DNA sequencing revealed an open reading frame of 1,068 nucleotides capable of encoding 356 amino acids which yields a protein with a molecular weight of 38,584. The hydropathy profile of the polypeptide indicated a putative N-terminal signal sequence of 44 amino acid residues. IrpA is a cytoplasmic membrane protein as determined by biochemistry and electron microscopy immunocytochemistry. The upstream region of the irpA gene contained a consensus sequence similar to the aerobactin operator in Escherichia coli. This fact, plus a mutant with a mutation in irpA that is unable to grow under iron-deficient conditions, led us to suggest that irpA is regulated by iron and that the gene product is involved in iron acquisition or storage.

Amino Acid Sequence↗
PubMed1987

The role of clinical examination in the accurate diagnosis of bovine neurologic disease.

Accurate, specific diagnosis of bovine neurologic disease is both possible and necessary in practice settings. The requirements for accurate diagnosis are a knowledge of the pathogenesis and epizootiology of the bovine neurologic diseases as described in this issue and a systematic approach to clinical examinations including accurate history taking, careful physical examination, neurologic examination, and inspection of the environment. Support for an accurate diagnosis can be obtained by use of the clinical pathology laboratory and, in herd problems, necropsy. The value of a precise diagnosis in bovine neurologic disease lies in the avoidance of costly, inappropriate therapy, the restriction of transmission of zoonotic disease, avoidance of ineffective treatment, more efficient salvage of affected individuals, and cost-efficient implementation of appropriate preventive measures as well as a sense of professional satisfaction in overcoming a challenging and difficult diagnostic problem.

Animals↗
PubMed1987

Localized diseases of the bovine brain and spinal cord.

Localized lesions of the central nervous system do occur in cattle. Those affecting the cranial nerves and focal lesions of the spinal cord are most easily recognized by careful neurologic examination. Once the lesion has been anatomically localized, likely etiologic causes can be pursued. Probably the most common cause of cranial nerve deficits in cattle is listeriosis. Important differential diagnoses include brain and pituitary abscesses and extensions of ear infections. Other possible causes include PEM, TEME, hypovitaminosis A, and several rare, sporadic causes. In young cattle, spinal trauma and vertebral body abscesses are the most common causes of progressive paresis resulting from spinal cord lesions. Congenital abnormalities must be considered in the differential diagnoses for very young calves. Non-neurologic conditions, including fractures of the limbs and especially nutritional muscular dystrophy, must be ruled out. In older cattle, compressive neoplasms, most notably lymphosarcoma, are primarily responsible for progressive paresis. Differential diagnosis should include other neurologic conditions such as delayed organophosphate neurotoxicity; early progressive diffuse neurologic diseases such as rabies, pseudorabies, and botulism; plant toxicities; and non-neurologic conditions resulting in recumbency, such as hypocalcemia and musculoskeletal trauma.

Animals↗
PubMed1986

Vertebral body abscesses in cattle: a review of five cases.

Over a 4-year period, vertebral body abscess (VBA) was diagnosed in 5 young cattle at the University of Minnesota, College of Veterinary Medicine. Review of these cases indicated that laboratory findings may not support a diagnosis of VBA and that the most important basis for diagnosis of this condition is a thorough neurologic examination. In 4 cases, necropsy revealed abscesses in the lungs or thoracic cavity as well, suggesting that a history of pneumonia preceding paresis may favor the diagnosis of VBA.

Abscess↗
PubMed1985

New method for visualization of vascular networks in nonperfused fixed tissues.

A new method of visualizing the angioarchitecture of tissues has been developed that uses blood components in nonperfused materials. Tissue blocks are fixed in 4% paraformaldehyde and cut with a vibratome into 50-60 micron sections. Endogenous peroxidase in red blood cells is then reduced in the presence of hydrogen peroxide with the resultant oxidation of the chromogen 3,3'-diaminobenzidine (DAB). This generates a dark, highly insoluble reaction product throughout the vascular system. The visualization of vascular components can be further enhanced by exposing the sections to peroxidase-conjugated IgG to increase the background staining of the blood plasma. The technique minimizes preparation artifact and permits the application of morphometric analytical methods, thus allowing parameters such as the volume density of the vascular bed to be quantified.

3,3'-Diaminobenzidine↗
PubMed1984

Agar gel immunodiffusion test for diagnosis of clinical paratuberculosis in cattle.

During a 19-month period, the agar gel immunodiffusion (AGID) test was used as an aid in differential diagnosis of paratuberculosis in 51 cattle with a history of chronic weight loss and/or chronic diarrhea. Thirty-three cattle were AGID test-positive for paratuberculosis. Twenty-eight cattle (87.5%) yielded Mycobacterium paratuberculosis from bacterial culture of feces. Four cattle were confirmed as having paratuberculosis on necropsy. One had a negative fecal culture but was lost to follow-up. Thus, 32 of the 33 AGID test-positive cattle (96.9%) were confirmed as paratuberculous by culture or necropsy. Of the 18 cattle that were AGID test-negative, 17 (94%) also were culture-negative after 12 to 20 weeks' incubation of the culture tubes. Direct fecal smears from 29 confirmed paratuberculous cattle were examined. Twenty-three (79.3%) had smears positive for M paratuberculosis. Fifteen culture-negative cattle were examined by direct smear; the results were negative for all.

Animals↗
PubMed1984

Neuronal and neurovascular integration following transplantation of the fetal hypothalamus into the third cerebral ventricle of adult Brattleboro rats. Neurological transplants: I.

This investigation has confronted some very basic questions of neurobiology and specifically deals with the neurovascular and neuroanatomical interactions that occur between graft and host following neural transplantation. Host Long-Evans rats with chronic autosomal diabetes insipidus (DI) received stereotaxic implants of normal 17 day post-coitus fetal hypothalamic fragments from the rostral (anterior) hypothalamus of normal Long-Evans pups. Following stereotaxic surgery DI hosts were killed 60 or 90 days later and their brain prepared for correlative microangiography-immunocytochemistry coupled with transmission electron microscopy. Explants were rapidly invaded by host vessels from several routes. (1) Vessels appeared to arise from portal capillaries in the underlying median eminence and (2) from adjacent vessels from the paraventricular nucleus and surrounding endocrine hypothalamus and (3) possibly from intrinsic vessels of the graft. The former remained fenestrated and established bonafide neurovascular zones in the ventral regions and in actively growing explants. Small clusters of arginine vasopressin-positive fibers and neurophysin positive neurons were noted throughout the parenchyma of explants. Despite the presence of neurosecretory neurons and neurovascular (neurohemal) zones, none of the host rats exhibited a physiological return to normal parameters of water balance. However the active growth and development of explants in the third cerebral ventricle of DI host rats coupled with emergence of neurovascular zones lends support to a potential model for analyzing the development of anatomical substrates for the central delivery of neuropeptide hormones.

Animals↗