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Biomedical subjects

M Valtonen

Publications and source records attributed to M Valtonen.

At least 55 records · Page 3Linked to original sources
PubMed1995

Capnocytophaga canimorsus septicemia: fifth report of a cat-associated infection and five other cases.

Capnocytophaga canimorsus is a fastidious, slow-growing, gram-negative, rod-shaped bacterium that belongs to the normal oral flora of dogs and cats. Human septicemic infections are associated with a high mortality; most cases occur in immunocompromised patients with a history of dog bite. The fifth case of cat-associated septicemia caused by Capnocytophaga canimorsus is described. The six case reports presented here point out the characteristics reported previously: (a) cats are a source of human infection; (b) alcohol abuse is an important risk factor for the development of septicemic Capnocytophaga canimorsus infection; (c) septicemic infection often manifests with disseminated intravascular consumption coagulopathy or purpura; and (d) some cases of septicemia in humans result from pets that lick skin ulcers.

Adult↗
PubMed1995

Effects of dexmedetomidine on coronary hemodynamics and myocardial oxygen balance.

OBJECTIVE: alpha 2-adrenergic agonists decrease central sympathetic outflow and maintain normal transmural myocardial blood flow distribution, but intravenous bolus doses of these agents can also induce excessive coronary vasoconstriction and myocardial ischemia. The hypothesis of the present study was that a rapid intravenous bolus of dexmedetomidine, a specific alpha 2-adrenergic agonist, will cause coronary vasoconstriction and accompanying myocardial ischemia in young pigs. DESIGN: Prospective, controlled study on experimental animals. SETTING: Animal laboratory of a university cardiorespiratory research center. PARTICIPANTS: Twelve domestic 8-week-old open-chest pigs, anesthetized with high-dose fentanyl. Another six pigs served as controls. INTERVENTIONS: Sequential intravenous dexmedetomidine boluses of 3, 10, and 30 mg/kg were administered, and responses were measured during peak changes (2 minutes after injection) and during recovery after each dose. MEASUREMENTS AND MAIN RESULTS: Left anterior descending coronary artery blood flow, calculated regional coronary vascular resistance, myocardial extraction of oxygen and lactate, plasma catecholamine levels, and conventional central hemodynamic parameters were measured. The two higher doses of dexmedetomidine induced 21% and 29% immediate increases in left anterior descending coronary artery blood flow. At the same time mean systemic blood pressure and pulmonary capillary wedge pressure increased, and calculated regional coronary vascular resistance increased. Myocardial extraction of oxygen and lactate remained unchanged. CONCLUSIONS: Large intravenous doses of dexmedetomidine caused moderate regional coronary vasoconstriction without metabolic signs of myocardial ischemia in young domestic pigs at the same time as a marked vasoconstrictive response in the systemic circulation.

Adrenergic alpha-Agonists↗
PubMed1995

Effects of melatonin implants in spring on testicular regression and moulting in adult male raccoon dogs (Nyctereutes procynoides).

Six male raccoon dogs were treated with constant-release implants of melatonin on 29 March, when the animals still had mature spermatozoa and a winter coat. Six untreated animals served as controls. High serum concentrations of melatonin were found in the treated animals throughout the study period (182.2 and 38.5 pg ml-1 in April and August, respectively). The high serum concentrations of prolactin in April and May (18.9 and 15.7 ng ml-1, respectively) in the controls were not seen in the treated animals. Testicular regression, judged by width of the testis and stage of spermatogenesis, was slowed after melatonin administration. Testis width from April to June and stage of spermatogenesis in May and June were greater in the treated animals than in the controls; however, from July onwards the differences between the two groups were no longer significant. Serum concentrations of testosterone remained low (below the detection limit in most cases) in both treated and control animals throughout the study period. Melatonin treatment also affected moulting, which was assessed by changes in the number of growing and mature underfur hairs per bundle and the percentage of bundles with a growing guard hair. The treated animals showed a more rapid shedding of mature underfur hairs and growth of new underfur hairs 6 weeks after melatonin implantation compared with the controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Four fatal cases of nephropathia epidemica.

Four serologically confirmed fatal cases of nephropathia epidemica (NE), the mild form of hemorrhagic fever with renal syndrome (HFRS) are described. All the patients had disseminated intravascular coagulation. Autopsies revealed hemorrhage and necrotic areas of their pituitary glands, myocarditis, venous congestion and hemorrhage of the kidneys as well as pulmonary edema and hemorrhage of the lungs in all patients. This report provides new evidence that NE can be a fatal disease.

Adult↗
PubMed1995

Myocardial reperfusion after coronary bypass surgery. Suture of only distal or all anastomoses with the aorta cross-clamped?

Sixty patients undergoing elective coronary artery bypass grafting were randomly allocated into two groups, each of 30 patients and similar as regards age, sex, number of coronary artery bypasses and left ventricular ejection fraction. In group A the proximal anastomoses of vein grafts were sutured after aortic declamping during partial occlusion of the aorta, and in group B these anastomoses were done during aortic cross-clamping. The aortic cross-clamp time was significantly longer in group B than in group A (72 vs 57 min, p < 0.0001). Myocardial cooling and rewarming and the number of sustained or possible perioperative myocardial infarctions were equal in both groups. Central haemodynamics showed no intergroup difference, before or after induction of anaesthesia or at the end of surgery. Conduction disturbances were more common in group A than in group B (12 vs 3, p = 0.0246), and transient external pacing was more often required in group A (9 vs 2, p = 0.0534). Myocardial reperfusion via native coronary arteries and bypass grafts gives better protection against conduction disturbances than does reperfusion via only native arteries, despite longer aortic cross-clamping time.

Anastomosis, Surgical↗
PubMed1995

Low-field MR imaging for the assessment of therapy response in musculoskeletal infections.

Fifty-one patients with musculoskeletal infection were imaged by repeated MR imaging at ultra low-field and low-field strength. Soft-tissue infection, osteomyelitis, septic arthritis, and spondylitis were studied. The MR finding was scored according to the signal intensity (SI) on T2-weighted images (T2WI), and correlated with the values of serum C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and peripheral white blood cell (WBC) count. There was a positive correlation between the MR score and both CRP and ESR, but no correlation between MR score and WBC. The MR score between the follow-up studies decreased significantly in accordance with clinical reconstitution. The MR finding according to the SI on T2WIs corresponded better to disease activity than did the CRP or ESR.

Adolescent↗
PubMed1994

Association of Stomatococcus mucilaginosus with cholangitis.

The first case of cholangitis in which Stomatococcus mucilaginosus was cultured from bile is reported. A 64-year-old male became icteric and was shown to have gallstones in the gallbladder and a common bile duct stone which was removed endoscopically. As the patient remained icteric for a month thereafter the gallbladder with stones was removed. No common bile duct stone was shown by cholangiography perioperatively. The liver biopsy revealed cholangitis and Stomatococcus mucilaginosus was grown from the bile. The patient was cured by cholecystectomy without any antimicrobial therapy.

Bile↗
PubMed1994

Combined cardioplegia delivery offers no advantage over antegrade cardioplegia administration in coronary surgical patients with a preserved left ventricular function.

The effects of antegrade and of combined antegrade and retrograde cardioplegia were compared in 101 patients undergoing elective coronary artery surgery. The patients were randomly allocated to two groups: antegrade cardioplegia was administered in 53 patients and combined cardioplegia in 43 patients. The patients of the two groups were similar in age, sex and left ventricular ejection fraction. Aortic clamping time and the number of coronary bypasses were equal in the groups. The ventricular septal temperature was measured continuously during cardioplegia administration, after each distal anastomosis accomplished, and continuously after aortic declamping. Serum CK-MB activities were serially measured for up to 3 days postoperatively. Electrocardiograms (ECG) were taken preoperatively, as well as on the first, second and eighth postoperative days. The left ventricular function was evaluated with a volume load test preoperatively and on the first postoperative morning. The two groups were similar with respect to myocardial cooling, response to volume loading, the number of patients with perioperative myocardial infarctions, cardiac arrhythmias or atrioventricular conduction blocks and clinical outcome. However, the CK-MB activities were lower in the antegrade group suggesting better myocardial protection in an unselected group of patients undergoing coronary artery bypass grafting.

Analysis of Variance↗
PubMed1993

Renal melatonin excretion in sheep is enhanced by water diuresis.

Diurnal variation in blood melatonin levels and renal melatonin excretion was monitored in five ewes by blood sampling and quantitative urine collection at 2-h intervals. A typical secretory pattern of melatonin was seen both in blood and urine levels and in the renal excretion of melatonin. Serum melatonin levels increased from daytime values of approximately 200 pmol/l to a mean of 800 pmol/l during darkness. Urine flow rate and urine osmolality did not show any clear diurnal rhythm. To examine whether urine flow rate affects renal melatonin excretion at night, urine was collected in three consecutive 30-min fractions, and blood was sampled in the middle of each urine collection period when the sheep were in normal water balance or after hydration. Hydration increased urine flow rate over sixfold and decreased urine osmolality well below plasma osmolality. Glomerular filtration rate, measured as creatinine clearance, did not change. Serum melatonin concentrations did not differ between hydrated and non-hydrated sheep. However, urinary melatonin excretion was 1.1 +/- 0.3 (S.E.M.) pmol/min at midnight in normal water balance, and significantly higher (2.6 +/- 0.4 pmol/min) in the hydrated state. In this study, the validity of urinary melatonin determinations as an indicator of pineal function was confirmed in normal water balance. In addition, our results suggest that a high tubular fluid load during diuresis increases urinary melatonin excretion because of decreased tubular reabsorption.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Species-specific features of oestrous development and blastogenesis in domestic canine species.

The reproductive physiology of taxonomically closely related species is usually very similar. The main difference in the reproduction of the dog and fox is the length of the different phases of the oestrous cycle. Pro-oestrus and oestrus are longest in the dog: oestrus lasts 3-5 days in the blue fox and 1-3 days in the silver fox, compared with about 1 week in the dog. The profiles of sex steroid concentrations in plasma during oestrus and pregnancy are similar and the luteal phase in non-pregnant animals is prolonged, progesterone concentrations reaching a maximum by 15-30 days after the luteinizing hormone (LH) peak in the dog, by 10-20 days in the blue fox and by 5-15 days in the silver fox. The duration from LH surge to ovulation is about the same in the dog and fox, but thereafter the oocytes and early embryos develop faster in foxes than in the dog. The tubal transport time is 4-6 days in the silver fox, embryos entering the uterus at the 4-16-cell stage. In the blue fox the oocytes remain in the oviducts for 8-10 days, developing into the morula stage, whereas in the dog a still longer oviductal phase results in embryos that are at the compact morula or blastocyst stage when entering the uterus. The preimplantation period is about 1 week in the dog and the blue fox, but 9-10 days in the silver fox.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Comparison of propofol infusion and isoflurane for maintenance of anesthesia for dentistry in mentally retarded patients.

A continuous infusion of propofol following an induction dose of 2 mg/kg was compared with thiopental/isoflurane for the induction and maintenance of anesthesia in 20 mentally retarded outpatients undergoing routine dental procedures. The infusion rate of propofol and the concentration of isoflurane were adjusted to maintain the heart rate and blood pressure within +/- 25% of the baseline values. Postoperative wakefulness was assessed using a 100-mm visual analogue scale at the time of extubation and at 5, 10, 15, 30, 60, 90, and 120 min after extubation. Both agents provided adequate anesthesia for the treatment, and no major adverse reactions occurred. Recovery was more complete during the first hour after extubation in the propofol group, and these patients were discharged earlier.

Adolescent↗
PubMed1992

Hypotensive anesthesia for middle ear surgery: a comparison of propofol infusion and isoflurane.

An infusion of propofol (2,6-diisopropylphenol) was compared with isoflurane to induce hypotension for middle ear surgery. Forty patients (ASA physical status I-II, 16-55 years) scheduled for elective surgery were included in an open randomized study. The pharmacokinetics of propofol infusion were also studied in 6 patients. Both agents produced controlled hypotension (MAP reduction of 30% from the baseline values) with an acceptable visibility of the surgical field. No major complications occurred. The mean total dose of propofol infusion was 6.4 +/- 2.7 mg/kg and the mean concentration of isoflurane was 0.9 +/- 0.4%. Considerable interindividual pharmacokinetic variability was found and propofol was extensively distributed and rapidly cleared from the body after the infusion. Propofol infusion may be a new alternative as a hypotensive agent in middle ear surgery.

Adolescent↗