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Biomedical subjects

A M Kaiser

Publications and source records attributed to A M Kaiser.

At least 19 recordsLinked to original sources
PubMed2006

The prognostic impact of the time interval to recurrence for the mortality in recurrent colorectal cancer.

OBJECTIVE: The risk of a cancer recurrence has been correlated with the stage of the primary tumour at the time of presentation. However, once a recurrence has developed, the primary tumour stage may not be the determining prognostic factor anymore. The objective of this study was (i) to evaluate the association between the recurrence interval and the outcome of the recurrence, and (ii) to determine whether that interval was affected by the use of adjuvant radiation and/or chemotherapy. METHOD: This retrospective study analysed 212 patients who developed recurrent colorectal cancer from 1987 to 1993. Primary parameters such as age, gender, primary tumour site and stage, and use of postoperative adjuvant treatment were correlated with the recurrence interval, the type and site of the recurrence (i.e. locoregional vs distant metastases), and the outcome. Uni- and multivariate analysis was used to compare the recurrence interval and survival between different subgroups as defined by risk factors. RESULTS: The mean time between the primary and the recurrent tumour was 25 months (range 1-252 months) with 82% of the recurrences developing within 3 years after surgery. The recurrence interval was inversely correlated with the initial tumour stage. Poor survival was associated with a short recurrence interval (less than 12 months) and a distant recurrence site. Even after adjusting for the initial tumour stage, the use of adjuvant treatment did not prolong the interval, i.e. delay the onset of recurrent cancer. CONCLUSION: The recurrence interval of colorectal cancer is a prognostic factor. However, the use of adjuvant therapy did not prolong that interval.

Adult↗
PubMed2005

[Resistant microorganisms in patients transferred from foreign hospitals].

OBJECTIVE: To determine the prevalence of carriers of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE) and gentamicin-resistant Gram-negative bacilli (GGNB) in patients repatriated from foreign hospitals to The Netherlands. DESIGN: Determination of prevalence. METHOD: In the period May 1998-August 2001, 1167 patients were repatriated. Swab specimens, demographic data and clinical data were obtained during the transfer. RESULTS: The prevalence of carriers of resistant microorganisms was 18.2%. MRSA was carried by 2.7% of the total repatriated group and by 4.7% of patients transferred to a Dutch hospital. Risk factors were antimicrobial treatment (odds ratio (OR): 3.4; 95% CI: 1.2-9.7), length of stay in a foreign hospital > or = 14 days (OR: 5.4; 95% CI: 2.3-12) and artificial ventilation (OR: 8.5; 95% CI: 1.8-41). VRE and GGNB were isolated from 2.7% and 14.1% of patients, respectively. Transfer from Asia or southern, south-eastern and eastern Europe were risk factors for carrying GGNB. CONCLUSION: Carriership of resistant microorganisms was high among repatriated patients. The highest risk of GGNB was more closely associated with the country from which the patient was transferred than the antimicrobial treatment received in the foreign hospital.

Carrier State↗
PubMed2005

Nosocomial infections in a Dutch neonatal intensive care unit: surveillance study with definitions for infection specifically adapted for neonates.

The incidence of nosocomial infection in neonatal intensive care units (NICUs) is high compared with other wards. However, no definitions for hospital-acquired infection are available for NICUs. The aim of this study was to measure the incidence of such infections and to identify risk factors in the NICU of the VU University Medical Center, which serves as a level III regional NICU. For this purpose, a prospective surveillance was performed in 1998-2000. We designed definitions by adjusting the current definitions of the Centers for Disease Control and Prevention (CDC) for children <1 year of age. Birth weight was stratified into four categories and other baseline risk factors were dichotomized. Analysis of risk factors was performed by Cox regression with time-dependent variables. The relationship between the Clinical Risk Index for Babies (CRIB) and nosocomial infection was investigated. Furthermore, for a random sample of cases, we determined whether bloodstream infection and pneumonia would also have been identified with the CDC definitions. Seven hundred and forty-two neonates were included in the study. One hundred and ninety-one neonates developed 264 infections. Bloodstream infection (N=138, 14.9/1000 patient-days) and pneumonia (N=69, 7.5/1000 patient-days) were the most common infections. Of bloodstream infections, 59% were caused by coagulase-negative staphylococci; in 21% of neonates, blood cultures remained negative. In 25% of pneumonias, Enterobacteriaceae were the causative micro-organisms; 26% of cultures remained negative. Compared with the Nosocomial Infections Surveillance System (NNIS) of the CDC, our device utilization ratios and device-associated nosocomial infection rates were high. The main risk factors for bloodstream infection were birth weight [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.45-2.17] and parenteral feeding with hospital-pharmacy-produced, all-in-one mixture 'Minimix' (HR 3.69, 95%CI 2.03-6.69); administration of intravenous antibiotics (HR 0.39, 95%CI 0.26-0.56) was a protective risk factor. The main risk factors for pneumonia were low birth weight (HR 1.37, 95%CI 1.01-1.85) and mechanical ventilation (HR 9.69, 95%CI 4.60-20.4); intravenous antibiotics were protective (HR 0.37, 95%CI 0.21-0.64). In a subcohort of 232 very-low-birthweight neonates, the CRIB was not predictive for infection. With the CDC criteria, only 75% (21/28) of bloodstream infections and 87.5% of pneumonias (21/24) would have been identified. In conclusion, our local nosocomial infection rates are high compared with those of NICUs participating in the NNIS. This can be partially explained by: (1) the use of our definitions for nosocomial infection, which are more suitable for this patient category; and (2) the high device utilization ratios.

Bacteremia↗
PubMed2004

Carriage of resistant microorganisms in repatriates from foreign hospitals to The Netherlands.

In a prospective survey conducted between May 1998 and September 2001, the prevalence of carriage of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE) and gentamicin-resistant Gram-negative bacilli (GGNB) was determined in 1167 patients repatriated from foreign hospitals to The Netherlands. Swab specimens, demographic data and clinical data were obtained during transfer of the patients from the foreign hospitals. The total prevalence of carriage of resistant microorganisms was 18.2%. MRSA was carried by 2.7% of all patients, and by 4.7% of the patients repatriated to a Dutch hospital. Antimicrobial treatment (adjusted odds ratio (OR) 3.4; 95% confidence interval (CI) 1.2-9.7), length of stay in a foreign hospital of > 14 days (adjusted OR 5.4; 95% CI 2.3-12) and artificial ventilation (adjusted OR 8.5; 95% CI 1.8-41) were risk factors for carriage of MRSA. VRE and GGNB were isolated from 2.7% and 14.1% of the patients, respectively. Transfer from Asia, and southern, southeastern and eastern Europe, were risk factors for carriage of GGNB. These carriage rates were high compared to those found in patients in Dutch hospitals, where the rates are < 1% for MRSA, 2% for VRE, and 4.5% for GGNB. The highest risk of acquisition of GGNB was associated with the country from where the patient was repatriated, rather than with the antimicrobial treatment received by the individual patient in the foreign hospital.

Carrier State↗
PubMed2003

Ultra-sonic nebulizers as a potential source of methicillin-resistant Staphylococcus aureus causing an outbreak in a university tertiary care hospital.

An outbreak of methicillin-resistant Staphylococcus aureus (MRSA) occurred on a head and neck surgical (HNS) ward of a university hospital in Amsterdam. The outbreak lasted from May 2000 until November 2000, and MRSA spread to two intensive care units. Amplified fragment length polymorphism analysis indicated that a single clone was responsible for the outbreak. Phage-typing indicated that this clone was of a type that was uncommon in The Netherlands. Strict isolation of patients, according to the Dutch national guidelines, was instituted. During the outbreak, surveillance culture specimens, from patients, healthcare workers, and the environment, were obtained at regular intervals. MRSA was found in the dust filters of nebulizers through which air from the room was filtered and subsequently humidified. These nebulizers were used to humidify tracheostomies. The dust filters were not maintained according to the guidelines. Restricted use and cleaning and disinfection of all ultra-sonic nebulizers led to termination of the outbreak. The outbreak illustrates that to terminate transmission of outbreak strains of MRSA, meticulous measures are necessary, which not only include strict isolation precautions, but also decontamination of the environment. In addition, it demonstrates the necessity of adhering to cleaning and disinfection guidelines for all medical and nursing equipment used in the hospital.

Disease Outbreaks↗
PubMed2001

Surgical management of ulcerative colitis.

As long as our understanding of ulcerative colitis is too limited to allow a more specific, disease-targeted treatment, surgery will play an important role in the management of these patients. Careful interdisciplinary evaluation and counselling of patients with ulcerative colitis will permit to achieve the goals on an individual basis with maximum safety. Restorative proctocolectomy with an IPAA has evolved as the procedure of choice among four basic surgical options because it appears to be safe and carries a low mortality. Although the associated morbidity is not negligible, functional results are generally good and patient satisfaction is high.

Colitis, Ulcerative↗
PubMed2001

A simultaneous outbreak on a neonatal unit of two strains of multiply antibiotic resistant Klebsiella pneumoniae controllable only by ward closure.

Two aminoglycoside-resistant strains of Klebsiella pneumoniae caused an outbreak on the neonatal unit at St Thomas' Hospital. One, which affected 18 patients, was capsular type K18 and resistant to newer cephalosporins by the production of the extended-spectrum beta-lactamase SHV-2; the other, which colonized four patients, was capsular non-typeable and did not produce extended-spectrum beta-lactamase. Both strains were probably brought into the unit by carrier patients; the probable carrier of the non-typeable strain was transferred from another hospital but was negative on a single admission screen; the probable carrier of the K18 strain was not screened on admission because he had been born at St Thomas', but his mother had been transferred from another hospital. Despite intensive efforts to control the outbreak by standard methods of hand washing, screening, patient isolation and environmental cleaning, a total of 22 neonates on the unit eventually became colonized or infected. One of three patients with bacteraemia died. A small proportion of samples of expressed breast milk, electronic thermometers and oxygen saturation probes were contaminated by the K18 strain and may have contributed to some of the cross-infection, but this did not explain the extent of the outbreak. The outbreak was controlled only by opening a temporary ward for colonized neonates and another for newly born babies, which allowed the closure and cleaning of the main neonatal unit. Multiply antibiotic resistant klebsiellas may be highly epidemic and cause serious, difficult-to-control outbreaks on neonatal units. All patients, regardless of their admission history, should be screened on admission for carriage of multiply resistant enterobacteria by a sensitive method, and units should have plans for temporary ward closure should outbreaks occur.

Aminoglycosides↗
PubMed2001

Laparoscopic splenectomy.

PURPOSE: To study the safety and efficacy of laparoscopic splenectomy (LS) in patients with hematologic disorders requiring surgical intervention. PATIENTS AND METHODS: A series of 103 consecutive adult patients underwent LS between 1992 and 1997 at our teaching hospital. Data were collected prospectively. The indications for splenectomy included idiopathic thrombocytopenic purpura (ITP), hereditary spherocytosis, autoimmune hemolytic anemia, and thrombotic thrombocytopenic purpura. RESULTS: The mean spleen size was 14 cm (range 8.5-24 cm) and the mean weight was 263 g (range 40-210 g). Accessory spleens were detected in 12 patients with ITP and 17 patients in the study overall. In 12 patients, LS was combined with a laparoscopic cholecystectomy for gallstones. There were four conversions to open splenectomy, all for hemorrhage and all occurred in the first 50 patients. We have not converted a single patient in the last 2 years. The mean operative time was 161 minutes and was greater in the first 10 cases than the last 10. There were no deaths. Postoperative complications occurred in six patients, one necessitating a second procedure for a small-bowel obstruction. The average length of stay in the hospital was 2.5 days. After surgery, thrombocytopenia resolved in 84% of patients with ITP and anemia resolved in 92% of the patients with hereditary spherocytosis. After a mean follow-up of 38 months (range 2-565 months), four patients (6%) showed a relapse of ITP, three within 12 months of surgery. CONCLUSIONS: Laparoscopic splenectomy can be performed safely and effectively in a teaching institution. LS in comparison with open surgery offers the same efficacy in the control of hematologic disease with the additional benefits of a minimally invasive approach. Laparoscopic splenectomy should therefore be considered the technique of choice and should prompt earlier consideration of surgery for patients with selected hematologic disorders.

Adult↗
PubMed2001

History of laparoscopy.

The history of laparoscopic surgery demonstrates how a close interaction between technology and medical-surgical innovators permitted its ultimate development. Similar revolutions have occurred in information and communication technology and in molecular biology. Within less than 2 decades, surgical management has moved from a disease-oriented approach to one that is more patient-oriented. While the past decade was characterized by the issue of what could be accomplished laparoscopically, the future will focus on the question of which operations should really be performed by this approach.

History, 19th Century↗
PubMed2000

Outbreak of Bacillus cereus infections in a neonatal intensive care unit traced to balloons used in manual ventilation.

In 1998, an outbreak of systemic infections caused by Bacillus cereus occurred in the Neonatal Intensive Care Unit of the University Hospital Vrije Universiteit, Amsterdam, The Netherlands. Three neonates developed sepsis with positive blood cultures. One neonate died, and the other two neonates recovered. An environmental survey, a prospective surveillance study of neonates, and a case control study were performed, in combination with molecular typing, in order to identify potential sources and transmission routes of infection. Genotypic fingerprinting by amplified-fragment length polymorphism (AFLP) showed that the three infections were caused by a single clonal type of B. cereus. The same strain was found in trachea aspirate specimens of 35 other neonates. The case control study showed mechanical ventilation with a Sensormedics ventilation machine to be a risk factor for colonization and/or infection (odds ratio, 9.8; 95% confidence interval, 1.1 to 88.2). Prospective surveillance showed that colonization with B. cereus occurred exclusively in the respiratory tract of mechanically ventilated neonates. The epidemic strain of B. cereus was found on the hands of nursing staff and in balloons used for manual ventilation. Sterilization of these balloons ended the outbreak. We conclude that B. cereus can cause outbreaks of severe opportunistic infection in neonates. Typing by AFLP proved very useful in the identification of the outbreak and in the analysis of strains recovered from the environment to trace the cause of the epidemic.

Bacillaceae Infections↗
PubMed1999

Repetitive short-term obstructions of the common bile-pancreatic duct induce severe acute pancreatitis in the opossum.

Gallstone pancreatitis is triggered by migrating stones that cause transient or continuous bile-pancreatic duct obstruction. One might hypothesize that the great clinical variability of acute pancreatitis is related to the inconsistent number and duration of a series of stone migrations. A new setting for the opossum model of acute pancreatitis was developed allowing reversible bile-pancreatic duct obstructions. We compared the effects, on the pancreas and pancreatitis severity, of repeated transient obstructions to those of continuous obstruction of varying duration. Repetitive intermittent duct obstruction in American opossums was achieved using an extraductal balloon occluder connected to a subcutaneous port system that was inflated three times for 24 hr within a five-day period. Continuous duct obstruction was achieved by duct ligation. Sham-operated animals served as controls. After one, three, or five days of continuous obstruction and at the end of the third consecutive 24-hr obstruction (day 5), animals were killed and the severity of pancreatitis was determined quantitating the extent of acinar cell necrosis, pancreatic edema, and acinar cell fragility. Three repetitive one-day periods (total 72 hr) of bile-pancreatic duct obstruction resulted in acute necrotizing pancreatitis. The severity of pancreatitis was similar to that observed after five days of continuous obstruction and was more severe than that noted after three days (72 hr) of continuous obstruction. In conclusion, these observations suggest that the pancreas is susceptible to sensitization by factors related to transient duct obstruction. A series of minor events such as repeated stone passage may thus contribute to the progression to severe pancreatitis.

Acute Disease↗
PubMed1999

Nosocomial outbreak of gentamicin-resistant Klebsiella pneumoniae in a neonatal intensive care unit controlled by a change in antibiotic policy.

Between August and November 1997, a nosocomial outbreak caused by gentamicin-resistant Klebsiella pneumoniae occurred in the Neonatal Intensive Care Unit (NICU) of our hospital. Thirteen neonates became colonized and three of them became infected. Comparison of the isolates by amplified fragment length polymorphism (AFLP) revealed clonal similarity for isolates of eight neonates (homology > 90%). Cultures from environmental specimens were negative for gentamicin-resistant K. pneumoniae. A case-control study was conducted to identify risk factors associated with acquisition of gentamicin-resistant K. pneumoniae. Risk factors were low gestational age and birth weight. These neonates need more care and handling and may therefore, be more at risk of colonization. Length of stay on the NICU was significantly longer for cases, but mean time until colonization (6.3 days) was shorter than the total stay for controls (9.5 days). No single member of the medical or nursing staff was significantly more involved with cases than with controls. The outbreak was stopped by replacing gentamicin by amikacin as the antibiotic of first choice whenever the use of an aminoglycoside antibiotic was indicated.

Amikacin↗
PubMed1998

Prospective, randomized comparison of extrapleural versus epidural analgesia for postthoracotomy pain.

BACKGROUND: Thoracic epidural analgesia is considered the method of choice for postthoracotomy analgesia, but it is not suitable for every patient and is associated with some risks and side effects. We therefore evaluated the effects of an extrapleural intercostal analgesia as an alternative to thoracic epidural analgesia. METHODS: In a prospective, randomized study, pain control, recovery of ventilatory function, and pulmonary complications were analyzed in patients undergoing elective lobectomy or bilobectomy. Two groups of 15 patients each were compared: one received a continuous extrapleural intercostal nerve blockade (T3 through T6) with bupivacaine through an indwelling catheter, the other was administered a combination of local anesthetics (bupivacaine) and opioid analgesics (fentanyl) through a thoracic epidural catheter. RESULTS: Both techniques were safe and highly effective in terms of pain relief and recovery of postoperative pulmonary function. However, minor differences were observed that, together with practical benefits, would favor extrapleural intercostal analgesia. CONCLUSIONS: These results led us to suggest that extrapleural intercostal analgesia might be a valuable alternative to thoracic epidural analgesia for pain control after thoracotomy and should particularly be considered in patients who do not qualify for thoracic epidural analgesia.

Analgesia↗
PubMed1998

Synthesis and action of the cyclic AMP antagonist, prostaglandylinositol cyclic phosphate (cyclic PIP), in Dictyostelium discoideum.

The cyclic AMP antagonist, prostaglandylinositol cyclic phosphate (cyclic PIP), is synthesized from prostaglandin E (PGE) and activated inositol phosphate (n-IP) in the presence of ATP by an enzyme of rat liver plasma membranes. Extracts of the slime mould Dictyostelium discoideum contain this activated inositol phosphate and D. discoideum cells convert [3H]PGE1 to [3H]cyclic PIP. This extracted polar [3H]product co-chromatographed with cyclic PIP from rat liver on gel filtration, anion exchange- and adsorption chromatography. Starving D. discoideum cells show cyclic AMP-induced oscillations, which can be inhibited by cyclic PIP (0.4 x 10(-7) M), but not by its phosphomonoester prostaglandylinositol phosphate (PIP) (1.4 x 10(-7) M). AMP and ADP at much higher concentrations (1 mM) antagonized these oscillations. The time needed for aggregation and fruiting body formation of starving D. discoideum cells is extended by cyclic PIP (1.4 x 10(-7) M) up to 3-fold, whereas its phosphomonoester (1.9 x 10(-7) M) showed a 9-fold weaker effect, and AMP and ADP even at 1 mM concentration showed no effect.

Animals↗