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Biomedical subjects

R Griffin

Publications and source records attributed to R Griffin.

At least 37 records · Page 2Linked to original sources
PubMed1993

Pharmacological characterization of cloned human NK-2 (neurokinin A) receptor expressed in a baculovirus/Sf-21 insect cell system.

Using the novel ligand [4,5-3H-Leu9]neurokinin A ([4,5-3H-Leu9] NKA) in a receptor binding assay, we characterized the pharmacology of a cloned neurokinin NK-2 receptor from human lung (hNK-2R), expressed in baculovirus-infected Sf-21 insect cells. Functional hNK-2R cDNA clones were isolated from human lung using a polymerase chain reaction-based methodology. hNK-2R was cloned into pAcYM1, a vector designed to couple expression to the polyhedrin promoter, and the recombinant baculovirus was isolated and used to infect Sf-21 insect cells. hNK-2R expression levels were monitored by Northern blots and 125-I-NKA binding assays. Isolates demonstrating the highest specific binding of 125-I-NKA were grown and membrane preparations from high-speed centrifugations were prepared from both hNK-2R-expressing and wild-type virus-infected cells. [3H]NKA bound in a protein-dependent, saturable (Bmax = 820 +/- 167 fmol/mg of protein), and highly specific (88 +/- 5%) manner to hNK-2R, but not to membranes from cells infected with wild-type virus (14 +/- 8%, 7 +/- 10 fmol/mg of protein). [3H]NKA binding was rapid (k1 = 0.085 nM-1 x min-1) and reversible (t1/2 = 4-5 min). Equilibrium binding experiments demonstrated binding to a mixture of receptors in high and low affinity states (Kd1 = 2.28 +/- 0.26 nM and Kd2 = 266 +/- 91 nM). Binding to hNK-2R was greatly enhanced (400%-600%) by Ca2+ and Mg2+ (EC50 values of 30 microM and 140 microM, respectively), whereas guanosine-5'-O-(3'-thio)triphosphate and guanosine-5'-(beta, gamma-imido)diphosphate were inhibitory. Competition experiments with agonists also demonstrated binding to high and low affinity states, with the following order of potency: NKA > [Nle10]NKA(4-10) > [beta-Ala8]NKA(4-10) >> substance P; Senktide and the NK-1 antagonist CP96,345 (10 microM) did not inhibit binding. Inhibition of binding by selective NK-2 antagonists was consistent with a single affinity state and demonstrated the following order of affinity: SR48,968 >> MEN10,376 > L659,877 > R396. These data suggest that infection of Sf-21 cells with baculovirus expression vector harboring the cDNA of hNK-2R resulted in expression of high affinity, G protein-coupled hNK-2R, with pharmacological selectivity compatible with the NK-2A receptor subtype.

Animals↗
PubMed1991

Structural studies of the mineral phase of calcifying cartilage.

The calcified cartilage of the epiphyseal growth plate of young calves has been studied by x-ray diffraction. Fourier transform infrared spectroscopy, magic angle 31P nuclear magnetic resonance spectroscopy, and chemical composition. The powdered tissue was separated by density centrifugation as a function of mineral content and thus qualitatively of the age of the calcium-phosphorus mineral phase. The individual density centrifugation fractions were examined separately. X-ray diffraction of the samples, especially of the lowest density fractions, revealed very poorly crystalline apatite. Fourier transform infrared spectroscopy and 31P nuclear magnetic resonance spectroscopy revealed the presence of significant amounts of nonapatitic phosphate ions. The concentration of such nonapatitic phosphates increases during the early stages of mineralization but then decreases as the mineral content steadily rises until full mineralization is achieved. The total concentration of carbonate ions was found to be much lower in calcified cartilage than in bone from the same organ (scapula). The carbonate ions are located in both A sites (OH-) and B sites (PO4(3-)), with a distribution similar to that found in bone mineral. However, discrepancies between infrared resolution factors of phosphate and carbonate bands are consistent with a heterogeneous distribution of carbonate ions in poorly organized domains of the solid phase of calcium phosphate. These initial studies permit one to characterize the calcium phosphate mineral phase as a very poorly crystalline, immature calcium phosphate apatite, rich in labile nonapatitic phosphate ions, with a low concentration of carbonate ions compared with bone mineral of the same animal, indeed from the bone of the same organ (scapula).

Animals↗
PubMed1991

Eosinophilic fasciitis is clinically distinguishable from the eosinophilia-myalgia syndrome and is not associated with L-tryptophan use.

Induration of the skin develops in a majority of patients with the eosinophilia-myalgia syndrome associated with L-tryptophan, and bears striking clinical and histopathological resemblance to eosinophilic fasciitis (EF). These similarities have led to the suggestion that eosinophilia-myalgia syndrome and EF are the same disease. To study the relationship of eosinophilia-myalgia syndrome and EF, we ascertained the prevalence of L-tryptophan use in a cohort of patients with EF, and compared their clinical and laboratory findings to those of patients with eosinophilia-myalgia syndrome associated cutaneous involvement. None of 11 patients who were diagnosed as having EF between 1970 and 1989 used L-tryptophan containing preparations prior to the onset of their illness. Marked clinical and laboratory test differences were observed between patients with EF and eosinophilia-myalgia syndrome. Patients with eosinophilia-myalgia syndrome had a more acute onset, more severe symptoms, higher frequency of rash and of pulmonary, cardiac, gastrointestinal, neurologic, myopathic and thyroid involvement compared to patients with EF. Corticosteroid therapy resulted in improvement of cutaneous involvement in 88% of patients with EF but it was only partially successful in patients with eosinophilia-myalgia syndrome. Hospitalization and fatalities occurred only among patients with eosinophilia-myalgia syndrome. These observations demonstrate that eosinophilia-myalgia syndrome is a more severe disease with multisystemic involvement that can be clinically distinguished from EF. In contrast to eosinophilia-myalgia syndrome, EF is not associated with L-tryptophan ingestion.

Adrenal Cortex Hormones↗
PubMed1986

A hospital cafeteria-related food-borne outbreak due to Bacillus cereus: unique features.

Although Bacillus cereus is a well-known cause of food-borne illness, hospital-related outbreaks of food-borne disease due to B. cereus have rarely been documented. We report a hospital employee cafeteria outbreak due to foods contaminated with B. cereus in which an outside caterer was employed to prepare the suspect meals. Data were collected from 249 of 291 employees who had eaten either of the two meals. With a mean incubation period of 12.5 hours, 64% (160 of 249) of employees manifested illness. Symptoms, which averaged 24.3 hours in duration, included diarrhea (96.3%), abdominal cramps (90%), nausea (50.6%), weakness (24.7%), and vomiting (13.8%). Eighty-seven employees sought medical attention, 84 of whom were seen in an emergency room. Although a significant difference was not demonstrated in food-specific attack rates, B. cereus was cultured from both rice and chicken items that were served at both meals. Sixty-three employees submitted stools for culture that grew no enteric pathogens, but none were examined for B. cereus. This food-borne outbreak demonstrates: the need for hospital kitchen supervisors to ensure proper handling of food when outside caterers are employed; that significant differences in food-specific attack rates may not be demonstrated in outbreaks, which may be related to several factors; and the importance of notifying microbiology laboratory personnel when B. cereus is a suspect enteric pathogen, since many laboratories do not routinely attempt to identify this organism in stool specimens.

Animals↗
PubMed1981

Prescription of home exercise therapy for cardiovascular fitness.

The importance of regular exercise activity in health maintenance has been continually emphasized. Family physicians, as the primary health care providers to many individuals, need a protocol for exercise prescription that is both practical for the physician to administer and reasonable for the patient to understand and follow. A practical protocol applicable to individuals of varying cardiac states is presented.

Angina Pectoris↗
PubMed1978

Alcoholic liver disease presenting with marked elevation of serum alkaline phosphatase. A combined clinical and pathological study.

Twenty patients with longstanding alcoholism and biopsy-proven alcoholic liver disease presented with marked elevation of serum alkaline phosphatase (in excess of four times the upper limit of normal). None had a past or present history to suggest pancreatitis or biliary tract disease, nor had any of these patients recently taken medication which could be implicated in cholestatic jaundice. Thirteen (65%) of this group either had radiologic or post mortem confirmation of nonobstructed biliary systems. The histologic findings in this group of patients were compared with those of a group of patients with alcoholic liver disease and normal or only mild elevation of serum alkaline phosphatase. Significantly more hepatocellular necrosis (P less than 0.05), alcoholic hyaline (P less than 0.02), and cholestasis (P less than 0.002) were noted in the severely hyperphosphatasemic group. Minimal degrees of steatosis were found in both groups. These data indicate that intrahepatic cholestasis occurs in patients with alcoholic liver disease, and this may often be secondary to alcoholic hepatitis. Overemphasis has previously been given to alcoholic fatty liver as a cause of this syndrome.

Adult↗
PubMed1975

The influence of ascorbic acid on platelet structure and function.

To determine the effect on platelet behavior of transient exposure of platelets to ascorbic acid, studies of platelet function and ultrastructure were done before exposure to ascorbic acid at pH 6.5, during exposure to pH 6.5, and after restoration of pH to pre-acidification levels. The effect of ascorbic acid (A.A.) was compared to that of HCl and citric acid (C.A.). ADP- and collagen-induced aggregation of normal platelets were significantly impaired by both A.A. and C.A. but were less affected by HCl. The release of 14C-serotonin was significantly reduced by each agent. The ultrastructure of normal platelets brought to pH 6.5 by A.A. was normal. After neutralization, there was marked dilatation of the open channel system and loss of the disc shape. When platelets were brought to pH 6.5 by A.A., then neutralized, the aggregates which formed after stimulation by ADP or collagen were smaller than normal, the platelets were less closely approximated, and degranulation was less complete. The data show that exposure of platelets to ascorbic acid for short intervals impairs their function when measured after restoration of pH to levels compatible with maximal responses. Platelet survival studies using autologous platelets labelled with 51Cr in the presence or absence of ascorbic acid showed that the recovery of normal platelets was unaffected by ascorbic acid, whereas recovery of platelets from patients with idiopathic thrombocytopenic purpura, idiopathic thrombocythemia, and alcohol-related thrombocytopenia was markedly reduced. The injury resulting from the use of ascorbic acid in preparing platelets for studies of platelet survival in patients with disorders affecting platelets may impair the recovery of the cells, resulting in artifactual changes in the survival studies.

Adenosine Diphosphate↗
PubMed1973

Tobacco and evoked potential.

Significant changes were found in two indices of the averaged visual evoked potentials in nine smokers after 12 and 36 hours of abstinence and after resumption of smoking. There was a decrease of the amplitude envelope accompanying withdrawal and an increase with resumption of smoking. These changes are consistent with the contention that tobacco increases arousal. Amplitude changes were found in a specific component of the evoked potential occurring between 100 and 125 milliseconds after the onset of the flash. The latter changes suggest the possibility that smoking selectively enhances the perceptiont of weak stimuli.

Adult↗
PubMed1970

Evoked response and behavior in cats.

Electroencephalographic averaged evoked responses to flashing lights of four different intensities were recorded in ten cats and correlated with behavior. Animals showing a high degree of exploratory behavior, aggressiveness, and activity and little withdrawal showed relatively large increases in amplitude of the averaged evoked response with increases of stimulus intensity. Those showing opposite behavioral traits had small increases or decreases of average evoked response amplitude with increases of stimulus intensity. These findings are compatible with those reported for human subjects. Inference is made about a neurophysiological mechanism for stimulus intensity modulation.

Aggression↗